CN112921288B - Preparation of high-energy-storage-density BaTiO 3 Ferroelectric thin film method, product and application thereof - Google Patents

Abstract

The disclosure relates to the technical field of thin film material preparation, and specifically provides a method for preparing a BaTiO ₃ ferroelectric thin film with high energy storage density and its product and application. The method for preparing a high energy storage density _BaTiO3 ferroelectric thin film comprises the following steps: substrate treatment, depositing a bottom electrode on the substrate, depositing a buffer layer on the bottom electrode, depositing a barium titanate dielectric layer on the buffer layer, depositing a barium titanate dielectric layer on the barium titanate The top electrode is deposited on the dielectric layer, and the bottom electrode is deposited on the substrate by radio frequency magnetron sputtering. The sputtering atmosphere of the radio frequency magnetron sputtering method is pure Ar, and the air pressure is controlled at 0.3Pa. The invention solves the problem in the prior art that the barium titanate thin film prepared by the in-situ method at medium and low temperature has poor performance and cannot meet the application requirements.

Description

A method for preparing high energy storage density BaTiO3 ferroelectric thin film and its product and application

technical field

The disclosure relates to the technical field of thin film material preparation, and specifically provides a method for preparing a BaTiO ₃ ferroelectric thin film with high energy storage density and its product and application.

Background technique

The statements herein merely provide background information related to the present disclosure and may not necessarily constitute prior art.

With the continuous advancement of technology, modern semiconductor devices have higher and higher requirements for miniaturization and integration. As a source of important functional device raw materials in the modern electronics industry, ferroelectric materials, especially ferroelectric thin films, have good properties such as ferroelectricity, piezoelectricity, and pyroelectricity, making them widely used in microelectronics, optoelectronics, and microelectronics. Mechanical systems and other fields have broad application prospects, and are one of the frontiers and hotspots of current scientific research. Among them, simple cubic perovskite-type ABO ₃ structure ferroelectric materials have a wide application potential in the electronics industry and ceramics industry due to their high dielectric constant, low dielectric loss, and excellent ferroelectric and piezoelectric properties.

Barium titanate (BaTiO ₃ , BTO for short) is a typical simple cubic perovskite type ABO ₃ ferroelectric material. As an important feature of the perovskite structure: the ions on the A and B positions can be replaced individually or in combination by various ions of different valences and radii (the A valence is +2 or +1; the B valence is +4 or +5 price), so that the properties of the material can be adjusted in a wide range to meet different application requirements.

In order to achieve compatibility with the CMOS process, the inventors provided a c-axis highly oriented barium titanate film and its in-situ fabrication method at medium and low temperatures in the previous research, although this method achieves better compatibility with the CMOS process compatibility, but the inventors found that the energy storage performance of the prepared barium titanate thin film is poor and cannot meet the application requirements.

Contents of the invention

Aiming at the problem that the barium titanate thin film prepared by the in-situ method at medium and low temperature in the prior art has poor performance and cannot meet application requirements.

In one or some embodiments of the present disclosure, a method for preparing a BaTiO ₃ ferroelectric thin film with high energy storage density is provided, comprising the following steps: substrate treatment, depositing a bottom electrode on the substrate, depositing a buffer layer on the bottom electrode, depositing a buffer layer on the buffer layer The barium titanate dielectric layer is deposited on the top electrode, and the top electrode is deposited on the barium titanate dielectric layer. The bottom electrode is deposited on the substrate by radio frequency magnetron sputtering. The sputtering atmosphere of the radio frequency magnetron sputtering method is pure Ar, keep low pressure sputtering.

In one or some embodiments of the present disclosure, a BaTiO ₃ ferroelectric thin film prepared by the above method for preparing a BaTiO ₃ ferroelectric thin film with high energy storage density is provided.

In one or some embodiments of the present disclosure, an application of the above-mentioned BaTiO ₃ ferroelectric thin film in an electronic chip is provided.

In one or some embodiments of the present disclosure, an application of the above-mentioned BaTiO ₃ ferroelectric thin film in an integrated device is provided.

One or some technical solutions in the above technical solutions have the following advantages or beneficial effects:

(1) In this disclosure, the BaTiO ₃ film prepared in situ at a medium and low temperature is nano-columnar crystal, and on the basis of the existing technology, the deposition pressure of the buffer layer is lowered, and the deposition pressure of the barium titanate film is increased. From the structural point of view , the barium titanate nano-columnar crystal structure prepared in the present disclosure is obvious and the lanthanum nickelate buffer layer has obvious effect. According to the electrical test, the ferroelectric properties and energy storage properties of the obtained thin film are excellent. The remnant polarization is 10μC/cm ² , the saturation polarization is 81μC/cm ² , the breakdown field is 8.1MV/cm, and the effective energy storage density is as high as 221J/cm ³ , the energy storage efficiency is 80%.

(2) BaTiO ₃ is a green and environmentally friendly lead-free and environmentally friendly ferroelectric ceramic material with simple element composition.

(3) The present disclosure is prepared under medium and low temperature conditions of 200°C to 500°C, which has a wider temperature range than the prior art of 350°C to 500°C, stronger operability, and is more compatible with the CMOS-Si process.

(4) The BaTiO ₃ thin film prepared by the magnetron sputtering method in the present disclosure has the advantages of good compactness, strong adhesion to the substrate, high flatness, and favorable industrialization.

(5) The BaTiO ₃ film buffer layer prepared in this disclosure is an ABO _3- type perovskite material, which better matches the BaTiO ₃ lattice and guides the growth of the BaTiO ₃ film into nano-columnar crystals, optimizing the orientation and electrical properties of the film .

(6) After improving the parameters in the present disclosure, the maximum polarization, the maximum applicable electric field and the cyclic energy storage density are greatly improved.

Description of drawings

The accompanying drawings constituting a part of the present disclosure are used to provide a further understanding of the present disclosure, and the exemplary embodiments and descriptions of the present disclosure are used to explain the present disclosure, and do not constitute improper limitations to the present disclosure.

Fig. 1 is a schematic diagram of the principle of the preparation method used in the embodiment of the present invention.

Figure 2 is a schematic diagram of the preparation of the top electrode mask used in the embodiment of the present invention, the diameter of the yellow top electrode can be 200 μm ~ 1000 μm, wherein, 1-Si single crystal substrate, 2-Pt/Ti bottom electrode, 3-lanthanum nickelate buffer layer, 4-barium titanate thin film, 5-gold top electrode, 6-gold electrode that conducts Pt/Ti bottom electrode and gold top electrode.

Fig. 3 is a schematic structural view of the barium titanate thin film system prepared in the embodiment of the present invention.

Fig. 4 is the TEM (prepared at 450°C) and XRD images of the barium titanate thin film prepared in the embodiment of the present invention.

FIG. 5 is a unilateral hysteresis loop (prepared at 350° C.) of the barium titanate thin film prepared in Example 1 of the present invention.

Fig. 6 is a unilateral hysteresis loop (prepared at 200° C.) of the barium titanate thin film prepared in Example 2 of the present invention.

Fig. 7 is a unilateral hysteresis loop (prepared at 500° C.) of the barium titanate thin film prepared in Example 3 of the present invention.

Detailed ways

The technical solutions in the embodiments of the present disclosure will be clearly and completely described below, obviously, the described embodiments are only a part of the embodiments of the present disclosure, rather than all the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by those skilled in the art without making creative efforts belong to the protection scope of the present disclosure.

Aiming at the problem that the barium titanate thin film prepared by the in-situ method at medium and low temperature in the prior art has poor performance and cannot meet application requirements.

In one or some embodiments of the present disclosure, a method for preparing a BaTiO ₃ ferroelectric thin film with high energy storage density is provided, comprising the following steps: substrate treatment, depositing a bottom electrode on the substrate, depositing a buffer layer on the bottom electrode, depositing a buffer layer on the buffer layer The barium titanate dielectric layer is deposited on the top electrode, and the top electrode is deposited on the barium titanate dielectric layer. The bottom electrode is deposited on the substrate by radio frequency magnetron sputtering. The sputtering atmosphere of the radio frequency magnetron sputtering method is pure Ar, keep low pressure sputtering.

Preferably, the gas pressure of the deposition buffer layer is controlled below 0.3Pa, excluding 0.3Pa;

Preferably, the gas pressure for depositing barium titanate is controlled to be higher than 1.2Pa, and does not contain 1.2Pa. The thin film prepared by magnetron sputtering has the following advantages: 1) high efficiency, 2) high density, 3) strong adhesion to the substrate, and 4) good flatness of the film layer. The principle of magnetron sputtering to prepare thin films is shown in Figure 1: under the action of electric field E, electrons collide with argon atoms during their flight to the substrate, causing them to ionize Ar ⁺ and generate a new electron. The electrons fly to the substrate, while the Ar ⁺ strikes the target under the acceleration of the high-voltage electric field. Atoms on the target surface break away from their lattice constraints by absorbing the kinetic energy of Ar ⁺ , escape from the target surface and fly to the substrate, and deposit on the substrate to form a thin film. Magnetron sputtering can be used to prepare a variety of thin film materials, such as metal films, ceramic films, polymer films, composite films and so on. There are many factors (such as gas flow, target power, temperature, coating atmosphere, etc.) that can affect the quality of the magnetron sputtering film, so each process parameter should be well controlled during the coating practice to improve the uniformity of the film and optimize its physical properties.

Preferably, the substrate treatment includes the following steps: select semiconductor substrate Si or Si/ _SiO2 as the substrate, perform ultrasonic cleaning with an ultrasonic cleaner to remove oily impurities, and remove the ultrasonic cleaner with deionized water, and then blow dry with an inert gas, Finally, place it in a vacuum coating chamber to evacuate;

Preferably, the ultrasonic cleaner is acetone, alcohol or a mixture of the two, more preferably a mixture of acetone and alcohol;

Preferably, the inert gas is nitrogen;

Preferably, the vacuuming in the vacuum coating chamber includes the following steps: vacuuming the back to 2×10 ^-4 Pa, and heating to 300°C.

Preferably, depositing the bottom electrode on the substrate includes the following steps: using a conductive metal target Ti/Pt to deposit a bottom electrode layer on the substrate by radio frequency or DC magnetron sputtering at the temperature of the substrate treatment process;

Preferably, the atmosphere during deposition is Ar,

Preferably, the Ar gas flow is controlled at 39 sccm,

Preferably, the air pressure is controlled at 0.3Pa,

Preferably, the target power is 55W,

Preferably, the total film thickness of the bottom electrode is 150 nm.

Preferably, depositing the buffer layer on the bottom electrode includes the following steps: using a _LaNiO3 target, maintaining the temperature at 200°C to 500°C, depositing the buffer layer on the substrate by radio frequency or DC magnetron sputtering;

Preferably, the atmosphere during deposition is a mixed gas of Ar and O ₂ ,

Preferably, the Ar gas flow is controlled at 60sccm, and the _O2 flow is controlled at 15sccm,

Preferably, the target power is 100W,

Preferably, the total film thickness of the buffer layer is 100nm;

Preferably, the temperature of radio frequency or direct current magnetron sputtering is 200°C-350°C. .

Preferably, depositing a barium titanate dielectric layer on the buffer layer includes the following steps: using a ceramic _BaTiO3 target and maintaining a temperature of 200°C to 500°C to deposit a _BaTiO3 layer on the bottom electrode by radio frequency magnetron sputtering,

Preferably, the sputtering atmosphere is a mixed gas of Ar and _O2 ,

Preferably, the Ar gas flow is controlled at 60sccm, and the _O2 flow is controlled at 15sccm,

Preferably, the air pressure is controlled at 1.2Pa,

Preferably, the sputtering power of the _BaTiO3 target is 100W,

Preferably, the thickness is 160-3000nm;

Preferably, the temperature of radio frequency magnetron sputtering is 200°C-350°C.

Preferably, depositing the top electrode on the barium titanate dielectric layer includes the following steps: using a metal target, depositing it by radio frequency or DC magnetron sputtering at room temperature, the sputtering atmosphere is air, and the target power density is 2 to 5 W/cm ^2. The diameter of the upper electrode is controlled at 200 μm to 1000 μm.

Preferably, the following steps are included:

(1) Substrate treatment:

Select the semiconductor substrate Si or Si/SiO ₂ as the substrate, ultrasonically clean it with acetone and alcohol to remove oily impurities on the surface, then clean it with deionized water, and then dry it with nitrogen, and finally Put it into the vacuum coating chamber, vacuum the back to 2×10 ^-4 Pa, and heat to 300°C;

(2) Deposit the bottom electrode on the substrate

Adopt conductive metal target material Ti/Pt, and under the temperature of step (1), deposit the bottom electrode layer on the substrate by means of radio frequency or DC magnetron sputtering, the atmosphere is Ar during deposition, the Ar gas flow is controlled at 39sccm, the air pressure Controlled at 0.3Pa, the target power is 55W, and the total film thickness of the bottom electrode is 150nm;

(3) Deposit a buffer layer on the bottom electrode

Use the LaNiO ₃ target with a higher matching degree with tetragonal barium titanate, and keep the temperature at 200 ° C ~ 500 ° C to deposit a buffer layer on the substrate by radio frequency or DC magnetron sputtering. The atmosphere during deposition is Ar and O ₂ mixed gas, the Ar gas flow rate is controlled at 60 sccm, the _O2 flow rate is controlled at 15 sccm, the air pressure is controlled at 0.3 Pa, the target power is 100 W, and the total film thickness of the buffer layer is 100 nm;

(4) Deposit a barium titanate dielectric layer on the buffer layer

Adopt ceramic BaTiO ₃ target, and keep the temperature in step (3) to deposit BaTiO ₃ layers on the bottom electrode in the mode of radio frequency magnetron sputtering, sputtering atmosphere is the mixed gas of Ar and _O , Ar gas flow is controlled at 60sccm , the O ₂ flow rate is controlled at 15sccm, the air pressure is controlled at 1.2Pa, the sputtering power of the BaTiO ₃ target is 100W, and the thickness is 160-3000nm;

(5) Deposit the top electrode on the barium titanate dielectric layer

A metal target is used, deposited by radio frequency or DC magnetron sputtering at room temperature, the sputtering atmosphere is air, the target power density is 2-5W/cm ² , and the diameter of the upper electrode is controlled at 200μm-1000μm.

In one or some embodiments of the present disclosure, a BaTiO ₃ ferroelectric thin film prepared by the above method for preparing a BaTiO ₃ ferroelectric thin film with high energy storage density is provided.

In one or some embodiments of the present disclosure, an application of the above-mentioned BaTiO ₃ ferroelectric thin film in an electronic chip is provided.

In one or some embodiments of the present disclosure, an application of the above-mentioned BaTiO ₃ ferroelectric thin film in an integrated device is provided.

Example 1

(1) Substrate treatment:

Select the semiconductor substrate Si or Si/SiO ₂ as the substrate, ultrasonically clean it with acetone and alcohol to remove oily impurities on the surface, then clean it with deionized water, and then dry it with nitrogen, and finally Put it into the vacuum coating chamber, vacuum the back to 2×10 ^-4 Pa, and heat to 300°C;

(2) Deposit the bottom electrode on the substrate

Adopt conductive metal target material Ti/Pt, and under the temperature of step (1), deposit the bottom electrode layer on the substrate by means of radio frequency or DC magnetron sputtering, the atmosphere is Ar during deposition, the Ar gas flow is controlled at 39sccm, the air pressure It is controlled at 0.3Pa, the target power is 55W, and the total film thickness of the bottom electrode is 150nm.

(3) Deposit a buffer layer on the bottom electrode

Use the LaNiO ₃ target with a higher degree of matching with the tetragonal phase barium titanate, and keep the temperature at 350°C to deposit the buffer layer on the substrate by radio frequency or DC magnetron sputtering. The atmosphere during deposition is a mixture of Ar and O ₂ Gas, the Ar gas flow is controlled at 60 sccm, the O ₂ flow is controlled at 15 sccm, the air pressure is controlled at 0.24Pa, the target power is 100W, and the total film thickness of the buffer layer is 100nm.

(4) Deposit a barium titanate dielectric layer on the buffer layer

Adopt ceramic BaTiO ₃ target, and keep the temperature in step (3) to deposit BaTiO ₃ layers on the bottom electrode in the mode of radio frequency magnetron sputtering, sputtering atmosphere is the mixed gas of Ar and _O , Ar gas flow is controlled at 60sccm , the O ₂ flow rate is controlled at 15 sccm, the air pressure is controlled at 1.7Pa, the sputtering power of the BaTiO ₃ target is 100W, and the thickness is 160-3000nm.

(5) Deposit the top electrode on the barium titanate dielectric layer

A metal target is used, deposited by radio frequency or DC magnetron sputtering at room temperature, the sputtering atmosphere is air, the target power density is 2-5W/cm ² , and the diameter of the upper electrode is controlled at 200μm-1000μm.

After the electrical performance test, the ferroelectric loop is shown in FIG. 5 . It can be seen from FIG. 5 that the ferroelectric thin film obtained in this embodiment has excellent energy storage performance.

Example 2

(1) Substrate treatment:

Select the semiconductor substrate Si or Si/SiO ₂ as the substrate, ultrasonically clean it with acetone and alcohol to remove oily impurities on the surface, then clean it with deionized water, and then dry it with nitrogen, and finally Put it into the vacuum coating chamber, vacuum the back to 2×10 ^-4 Pa, and heat to 300°C;

(2) Deposit the bottom electrode on the substrate

Adopt conductive metal target material Ti/Pt, and under the temperature of step (1), deposit the bottom electrode layer on the substrate by means of radio frequency or DC magnetron sputtering, the atmosphere is Ar during deposition, the Ar gas flow is controlled at 39sccm, the air pressure It is controlled at 0.3Pa, the target power is 55W, and the total film thickness of the bottom electrode is 150nm.

(3) Deposit a buffer layer on the bottom electrode

Using the LaNiO ₃ target with a higher degree of matching with the tetragonal barium titanate, the temperature is kept at 200°C to deposit a buffer layer on the substrate by radio frequency or DC magnetron sputtering, and the atmosphere during deposition is a mixture of Ar and O ₂ Gas, the Ar gas flow is controlled at 60 sccm, the O ₂ flow is controlled at 15 sccm, the air pressure is controlled at 0.18 Pa, the target power is 100 W, and the total film thickness of the buffer layer is 100 nm.

(4) Deposit a barium titanate dielectric layer on the buffer layer

Adopt ceramic BaTiO ₃ target, and keep the temperature in step (3) to deposit BaTiO ₃ layers on the bottom electrode in the mode of radio frequency magnetron sputtering, sputtering atmosphere is the mixed gas of Ar and _O , Ar gas flow is controlled at 60sccm , the O ₂ flow rate is controlled at 15 sccm, the air pressure is controlled at 1.6 Pa, the sputtering power of the BaTiO ₃ target is 100 W, and the thickness is 160-3000 nm.

(5) Deposit the top electrode on the barium titanate dielectric layer

A metal target is used, deposited by radio frequency or DC magnetron sputtering at room temperature, the sputtering atmosphere is air, the target power density is 2-5W/cm ² , and the diameter of the upper electrode is controlled at 200μm-1000μm.

Example 3

(1) Substrate treatment:

Select the semiconductor substrate Si or Si/SiO ₂ as the substrate, ultrasonically clean it with acetone and alcohol to remove oily impurities on the surface, then clean it with deionized water, and then dry it with nitrogen, and finally Put it into the vacuum coating chamber, vacuum the back to 2×10 ^-4 Pa, and heat to 300°C;

(2) Deposit the bottom electrode on the substrate

Adopt conductive metal target material Ti/Pt, and under the temperature of step (1), deposit the bottom electrode layer on the substrate by means of radio frequency or DC magnetron sputtering, the atmosphere is Ar during deposition, the Ar gas flow is controlled at 39sccm, the air pressure It is controlled at 0.3Pa, the target power is 55W, and the total film thickness of the bottom electrode is 150nm.

(3) Deposit a buffer layer on the bottom electrode

Use the LaNiO ₃ target with a higher degree of matching with the tetragonal phase barium titanate, and keep the temperature at 500°C to deposit the buffer layer on the substrate by radio frequency or DC magnetron sputtering. The atmosphere during deposition is a mixture of Ar and O ₂ Gas, the Ar gas flow is controlled at 60 sccm, the O ₂ flow is controlled at 15 sccm, the air pressure is controlled at 0.2 Pa, the target power is 100 W, and the total film thickness of the buffer layer is 100 nm.

(4) Deposit a barium titanate dielectric layer on the buffer layer

Adopt ceramic BaTiO ₃ target, and keep the temperature in step (3) to deposit BaTiO ₃ layers on the bottom electrode in the mode of radio frequency magnetron sputtering, sputtering atmosphere is the mixed gas of Ar and _O , Ar gas flow is controlled at 60sccm , the O ₂ flow rate is controlled at 15 sccm, the air pressure is controlled at 1.5Pa, the sputtering power of the BaTiO ₃ target is 100W, and the thickness is 160-3000nm.

(5) Deposit the top electrode on the barium titanate dielectric layer

A metal target is used, deposited by radio frequency or DC magnetron sputtering at room temperature, the sputtering atmosphere is air, the target power density is 2-5W/cm ² , and the diameter of the upper electrode is controlled at 200μm-1000μm.

The _BaTiO3 films prepared in Examples 1-3 were tested and analyzed by XRD and TEM respectively, and the film structure was nano-columnar crystals. As can be seen from Figure 4, the films prepared by the present application have relatively complete structures at various temperatures .

The above disclosures are only preferred embodiments of the present disclosure, and of course cannot be used to limit the scope of rights of the present disclosure. Therefore, equivalent changes made according to the patent scope of the present disclosure still fall within the scope of the present disclosure.

Claims (19)

1. Preparation of high-energy-storage-density BaTiO ₃ A method of making a ferroelectric thin film, comprising the steps of: treating a substrate, depositing a bottom electrode on the substrate, depositing a buffer layer on the bottom electrode, depositing a barium titanate dielectric layer on the buffer layer, and depositing a top electrode on the barium titanate dielectric layer, wherein the buffer layer deposition and the barium titanate deposition are completed by adopting a radio frequency magnetron sputtering method, the bottom electrode is subjected to radio frequency or direct current magnetron sputtering, and the sputtering atmosphere is pure Ar; ar and O for sputtering buffer layer and barium titanate dielectric layer ₂ The buffer layer is kept to be sputtered at low pressure, and the barium titanate film is kept to be sputtered at high pressure;

the step of depositing the buffer layer on the bottom electrode comprises the following steps: by using LaNiO ₃ The target material is used for depositing a buffer layer on the substrate in a radio frequency magnetron sputtering mode by keeping the temperature at 200-500 ℃;

the air pressure of the deposited buffer layer is controlled below 0.24 Pa;

the pressure of the deposited barium titanate is controlled to be more than 1.6 Pa; the matrix treatment comprises the following steps: selecting semiconductor substrate Si or Si/SiO ₂ As matrix, ultrasonic cleaning with ultrasonic detergent to remove oily impurities, and removing with deionized waterUltrasonic detergent, then blowing to dry by inert gas, and finally placing in a vacuum coating chamber for vacuumizing;

the bottom electrode is deposited on the substrate by the following steps: depositing a bottom electrode layer on a substrate by adopting a conductive metal target Ti/Pt in a radio frequency or direct current magnetron sputtering mode at the temperature of the substrate treatment process;

the method for depositing the barium titanate dielectric layer on the buffer layer comprises the following steps: adopts ceramic BaTiO ₃ Target, and depositing BaTiO on the buffer layer by means of radio frequency magnetron sputtering at a temperature of 200-500 DEG C ₃ A layer;

the deposition of the top electrode on the barium titanate dielectric layer comprises the following steps: depositing by using a metal target in a radio frequency or direct current magnetron sputtering mode at room temperature, wherein the sputtering atmosphere is air, and the target power density is 2-5W/cm ² The diameter of the upper electrode is controlled to be 200-1000 μm.

2. Preparation of high energy storage density BaTiO according to claim 1 ₃ The method for preparing the ferroelectric film is characterized in that the ultrasonic detergent is acetone, alcohol or a mixture of the acetone and the alcohol.

3. Preparation of high energy storage density BaTiO according to claim 1 ₃ A method for manufacturing a ferroelectric thin film, characterized in that the inert gas is nitrogen.

4. Preparation of high energy storage density BaTiO according to claim 1 ₃ The ferroelectric film method is characterized in that the step of vacuumizing in a vacuum coating chamber comprises the following steps: vacuum pumping the back to 2 × 10 ^-4 Pa, heating to 300 ℃.

5. Preparation of high energy storage density BaTiO according to claim 1 ₃ A method for forming a ferroelectric thin film, characterized in that the flow rate of Ar gas is controlled to 39sccm when a bottom electrode is deposited on a substrate.

6. Preparation of high energy storage density BaTiO according to claim 1 ₃ A method of forming a ferroelectric thin film, characterized byAnd when the bottom electrode is deposited on the substrate, the air pressure is controlled to be 0.3Pa.

7. The method for preparing high energy storage density BaTiO according to claim 1 ₃ A method of forming a ferroelectric thin film, characterized in that the target power is 55W when depositing a bottom electrode on a substrate.

8. Preparation of high energy storage density BaTiO according to claim 1 ₃ A method for forming a ferroelectric thin film, characterized in that, when a bottom electrode is deposited on a substrate, the total thickness of the bottom electrode is 150nm.

9. The method for preparing high energy storage density BaTiO according to claim 1 ₃ The ferroelectric thin film is prepared by depositing a buffer layer on a bottom electrode while controlling Ar gas flow at 60sccm ₂ The flow rate was controlled at 15sccm and the target power was 100W.

10. Preparation of high energy storage density BaTiO according to claim 1 ₃ A method for manufacturing a ferroelectric thin film, characterized in that, when a buffer layer is deposited on a bottom electrode, the total film thickness of the buffer layer is 100nm.

11. Preparation of high energy storage density BaTiO according to claim 1 ₃ The method for preparing the ferroelectric film is characterized in that when a buffer layer is deposited on a bottom electrode, the radio frequency or direct current magnetron sputtering temperature is 200-350 ℃.

12. The method for preparing high energy storage density BaTiO according to claim 1 ₃ The ferroelectric thin film is prepared by depositing a barium titanate dielectric layer on the buffer layer, controlling Ar gas flow at 60sccm ₂ The flow rate was controlled at 15 sccm.

13. Preparation of high energy storage density BaTiO according to claim 1 ₃ A method of forming a ferroelectric thin film, characterized in that, when depositing a barium titanate dielectric layer on a buffer layer, baTiO ₃ The sputtering power of the target was 100W.

14. The method for preparing high energy storage density BaTiO according to claim 1 ₃ The ferroelectric thin film is characterized in that the thickness of the barium titanate dielectric layer is 160-3000 nm when the barium titanate dielectric layer is deposited on the buffer layer.

15. Preparation of high energy storage density BaTiO according to claim 1 ₃ The ferroelectric film preparation method is characterized in that when the barium titanate dielectric layer is deposited on the buffer layer, the temperature of radio frequency magnetron sputtering is 200-350 ℃.

16. The method for preparing high energy storage density BaTiO according to claim 1 ₃ A method of making a ferroelectric thin film, comprising the steps of:

(1) Matrix treatment:

selecting semiconductor substrate Si or Si/SiO ₂ Ultrasonic cleaning with acetone and alcohol to remove oily impurities on the surface, final cleaning with deionized water, blow-drying with nitrogen gas, vacuum-pumping to 2 × 10 ^-4 Pa, heating to 300 ℃;

(2) Depositing a bottom electrode on a substrate

Adopting a conductive metal target material Ti/Pt, and depositing a bottom electrode layer on a substrate in a radio frequency or direct current magnetron sputtering mode at the temperature of the step (1), wherein the atmosphere during deposition is Ar, the flow rate of Ar is controlled at 39sccm, the air pressure is controlled at 0.3Pa, the target power is 55W, and the total film thickness of the bottom electrode is 150nm;

(3) Depositing a buffer layer on the bottom electrode

Adopts LaNiO with higher matching degree with tetragonal phase barium titanate ₃ The target material is used for depositing a buffer layer on a substrate in a radio frequency or direct current magnetron sputtering mode by keeping the temperature at 200-500 ℃, and the atmosphere during deposition is Ar and O ₂ The flow rate of Ar gas is controlled to be 60sccm ₂ Controlling the flow at 15sccm, controlling the air pressure below 0.24Pa, controlling the target power at 100W, and controlling the total film thickness of the buffer layer at 100nm;

(4) Depositing a barium titanate dielectric layer on the buffer layer

Using ceramic BaTiO ₃ Target, and maintaining the temperature in the step (3) to deposit BaTiO on the bottom electrode in a radio frequency magnetron sputtering mode ₃ Layer, sputtering atmosphere Ar and O ₂ The flow rate of Ar gas is controlled to be 60sccm ₂ The flow rate is controlled to be 15sccm, the air pressure is controlled to be more than 1.6Pa, and BaTiO ₃ The sputtering power of the target is 100W, and the thickness is 160-3000 nm;

(5) Depositing a top electrode on a barium titanate dielectric layer

Depositing by using a metal target in a radio frequency or direct current magnetron sputtering mode at room temperature, wherein the sputtering atmosphere is air, and the target power density is 2-5W/cm ² The diameter of the upper electrode is controlled to be 200-1000 μm.

17. The method for preparing BaTiO with high energy storage density according to any one of claims 1 to 16 ₃ BaTiO prepared by ferroelectric film method ₃ A ferroelectric thin film.

18. The BaTiO of claim 17 ₃ Use of a ferroelectric thin film in an electronic chip.

19. BaTiO of claim 17 ₃ Use of a ferroelectric thin film in an integrated device.

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