A high-polarization-strength and low-leakage-current-density antiferroelectric composite thin film, a preparation method and application thereof

Abstract

The application discloses a high-polarization-intensity and low-leakage-current-density antiferroelectric composite film and a preparation method and application thereof, and belongs to the technical field of inorganic thin film capacitor and memory preparation. The application aims to solve the problems of low polarization intensity and large leakage current density of existing inorganic capacitor and memory thin film. The high-polarization-intensity and low-leakage-current-density antiferroelectric composite film is composed of a functional layer and a lead zirconate layer; the functional layer is one or more of dioxidetantalum, zinc oxide or zirconium oxide. The application obtains an inorganic thin film with optimal performance by studying the material and the number of layers of the functional layer; the application prepares inorganic antiferroelectric composite films with three different functional layer materials by adopting a sol-gel method combined with a spin coating and annealing process, introduces the functional layer into the lead zirconate antiferroelectric thin film, reduces the leakage current density of the inorganic thin film, suppresses the polarization loss of the composite film, improves the polarization intensity of the composite film, and is favorable to improving the service life of a device.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of inorganic thin film capacitor and memory preparation, and particularly relates to a high-polarization-intensity and low-leakage-current-density antiferroelectric composite thin film and a preparation method and application thereof. BACKGROUND

[0002] Inorganic thin film materials have excellent electrical and optical properties and are widely used in dielectric, information storage, piezoelectric, photoelectric and other fields. Current inorganic thin film preparation processes include sol-gel method, chemical vapor deposition method, anodic oxidation method, magnetron sputtering method and spray pyrolysis method. The sol-gel process is widely used due to its high-quality film forming advantage. Inorganic antiferroelectric thin films have become a research hotspot in the field of dielectric capacitors and memories, but still face the bottleneck problems of low polarization intensity and high leakage current density of the thin film materials. Therefore, it is urgent to prepare an antiferroelectric composite thin film with high polarization intensity and low leakage current density. SUMMARY

[0003] The application aims to solve the problems of low polarization intensity and high leakage current density of existing inorganic capacitor and memory thin films, and provide an antiferroelectric composite thin film with high polarization intensity and low leakage current density and a preparation method and application thereof.

[0004] An antiferroelectric composite thin film with high polarization intensity and low leakage current density is composed of a functional layer and a lead zirconate layer.

[0005] The functional layer is one or more of tantalum pentoxide, zinc oxide or zirconium oxide.

[0006] A preparation method of an antiferroelectric composite thin film with high polarization intensity and low leakage current density is completed by the following steps:

[0007] I. Preparation of functional layer precursor solution:

[0008] The functional layer precursor solution is one or more of Ta2O5 precursor solution, ZnO precursor solution and ZrO2 precursor solution, and the preparation method is as follows:

[0009] ①, dissolve tantalum ethoxide in ethylene glycol methyl ether solution, stir at room temperature, and obtain Ta2O5 precursor solution;

[0010] ②, dissolve zinc nitrate in ethylene glycol methyl ether solution, heat and stir, and obtain ZnO precursor solution;

[0011] ③, dissolve zirconium n-propylate in ethylene glycol methyl ether solution, stir at room temperature, and obtain ZrO2 precursor solution;

[0012] II. Preparation of lead zirconate precursor solution:

[0013] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir until clear to obtain solution A; after cooling to room temperature, add zirconium n-propyl alcohol to solution A, and stir to obtain a lead zirconate precursor solution;

[0014] III. Preparation of antiferroelectric composite thin film

[0015] The functional layer precursor solution and the lead zirconate precursor solution are spin-coated on the substrate in sequence, and then the wet film is dried on a flat heater and then placed in a rapid annealing furnace for rapid annealing to obtain the antiferroelectric composite thin film with high polarization intensity and low leakage current density.

[0016] The antiferroelectric composite thin film with high polarization intensity and low leakage current density is applied in inorganic thin film capacitors or memories.

[0017] Advantages of the present application:

[0018] I. The present application uses sol-gel method combined with spin-coating annealing process to prepare an antiferroelectric composite thin film with high polarization intensity and low leakage current density; the functional layer is introduced into the lead zirconate antiferroelectric thin film to reduce the leakage current density of the inorganic thin film, inhibit the polarization loss of the composite thin film, and improve the polarization intensity of the composite thin film, which is beneficial to improve the service life of the device.

[0019] II. The antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared by the present application has low leakage current density and low polarization loss, and is suitable for the design of functional devices and the manufacture of flexible electronic devices when used as capacitors or memories.

[0020] III. The preparation process of the antiferroelectric composite thin film with high polarization intensity and low leakage current density provided by the present application is simple, the equipment is low in price, the selected materials are environmentally friendly and non-polluting, the harm to human body and environment caused by lead-based materials in the production and use process is overcome, and the present application is suitable for large-scale production. BRIEF DESCRIPTION OF DRAWINGS

[0021] Figure 1 FIG. 1 is a structural schematic diagram of the antiferroelectric composite thin film with high polarization intensity and low leakage current density in the present application;

[0022] Figure 2 FIG. 4 is an XRD comparison spectrum of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Examples 1-3;

[0023] Figure 3 FIG. 6 is an XRD comparison spectrum of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Examples 3-7;

[0024] Figure 4XRD comparison chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 3, 8, 9, comparative example 1 and comparative example 2;

[0025] Figure 5 Electric hysteresis loop chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 1-3;

[0026] Figure 6 Electric hysteresis loop chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 4-7;

[0027] Figure 7 Electric hysteresis loop chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 8, 9, comparative example 1 and comparative example 2;

[0028] Figure 8 Leakage current chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 3, 4, 5, 7;

[0029] Figure 9 Leakage current chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 8, 9 and comparative example 1;

[0030] Figure 10 Leakage current chart of high polarization intensity and low leakage current density antiferroelectric composite thin film prepared for example 1-2. DETAILED DESCRIPTION

[0031] In order to make the above objectives, features and advantages of the present application more obvious and easy to understand, the specific embodiments of the present application will be described in detail below in combination with the description examples.

[0032] In the following description, a lot of specific details are set forth in order to give a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, therefore, the present application is not limited by the specific examples disclosed below.

[0033] The experimental methods used in the following examples are all conventional methods unless otherwise specified. The materials, reagents, methods and instruments used are all conventional materials, reagents, methods and instruments in the art unless otherwise specified, and can be obtained by commercial channels by those skilled in the art.

[0034] Specific embodiment one: the high polarization intensity and low leakage current density antiferroelectric composite thin film of the present embodiment is characterized in that the antiferroelectric composite thin film is composed of a functional layer and a lead zirconate layer;

[0035] The functional layer is one or more of tantalum pentoxide, zinc oxide or zirconium oxide.

[0036] Specific embodiment two: the difference between this embodiment and specific embodiment one is that the thickness of the functional layer is 10-60 nm, and the thickness of the lead zirconate layer is 260-300 nm. The other steps are the same as those in specific embodiment one.

[0037] Specific embodiment three: the difference between this embodiment and one of specific embodiments one or two is that the preparation method of a high-polarization-strength and low-leakage-current-density antiferroelectric composite film is completed according to the following steps:

[0038] I. Preparation of a functional layer precursor solution:

[0039] The functional layer precursor solution is one or more of a Ta2O5 precursor solution, a ZnO precursor solution and a ZrO2 precursor solution, and the preparation method is as follows:

[0040] ①, dissolve tantalum ethoxide in ethylene glycol methyl ether solution, stir at room temperature, and obtain a Ta2O5 precursor solution;

[0041] ②, dissolve zinc nitrate in ethylene glycol methyl ether solution, heat and stir to obtain a ZnO precursor solution;

[0042] ③, dissolve zirconium n-propylate in ethylene glycol methyl ether solution, stir at room temperature, and obtain a ZrO2 precursor solution;

[0043] II. Preparation of a lead zirconate precursor solution:

[0044] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir until clear to obtain solution A; after cooling to room temperature, add zirconium n-propylate to solution A, stir, and obtain a lead zirconate precursor solution;

[0045] III. Preparation of an antiferroelectric composite film:

[0046] Spin-coat the functional layer precursor solution and the lead zirconate precursor solution on the substrate in turn, then dry the wet film on a flat plate heater, and then place it in a rapid annealing furnace for rapid annealing to obtain a high-polarization-strength and low-leakage-current-density antiferroelectric composite film.

[0047] Specific embodiment four: the difference between this embodiment and one of the specific embodiments one to three is that the concentration of the Ta2O5 precursor solution in step one ① is 0.02mol / L-0.03mol / L; the concentration of the ZnO precursor solution in step one ② is 0.04mol / L-0.06mol / L; the concentration of the ZrO2 precursor solution in step one ③ is 0.04mol / L-0.06mol / L. The other steps are the same as specific embodiments one to three.

[0048] Specific embodiment five: the difference between this embodiment and one of the specific embodiments one to four is that the concentration of the lead zirconate precursor solution in step two is 0.2mol / L-0.4mol / L. The other steps are the same as specific embodiments one to four.

[0049] Specific embodiment six: the difference between this embodiment and one of the specific embodiments one to five is that the temperature of the heating and stirring in step one ② is 60℃-70℃; the heating and stirring in step two is at 60℃ until clear; the substrate in step three is mica or Si substrate. The other steps are the same as specific embodiments one to five.

[0050] Specific embodiment seven: the difference between this embodiment and one of the specific embodiments one to six is that the spin coating process in step three is: first spin coating at 1000rmp, and then spin coating at 3500rmp. The other steps are the same as specific embodiments one to six.

[0051] Specific embodiment eight: the difference between this embodiment and one of the specific embodiments one to seven is that the temperature of the drying in step three is 400℃-430℃, and the time is 6min-10min. The other steps are the same as specific embodiments one to seven.

[0052] Specific embodiment nine: the difference between this embodiment and one of the specific embodiments one to eight is that the temperature of the annealing in step three is 740℃-760℃, and the time is 5min-10min. The other steps are the same as specific embodiments one to eight.

[0053] Specific embodiment ten: this embodiment is the application of a high-polarization-intensity and low-leakage-current-density antiferroelectric composite thin film in inorganic thin film capacitors or memories.

[0054] The beneficial effects of the present application are verified by the following examples:

[0055] Example 1: a high-polarization-intensity and low-leakage-current-density antiferroelectric composite thin film, which is composed of a tantalum pentoxide layer (Ta2O5) and a lead zirconate layer (PbZrO3), and is prepared by the following steps:

[0056] I. Preparation of Ta2O5 precursor solution:

[0057] Dissolve the tantalum ethoxide in the ethylene glycol methyl ether solution, and stir at room temperature to obtain the Ta2O5 precursor solution;

[0058] The concentration of the Ta2O5 precursor solution in step I is 0.025 mol / L;

[0059] II. Preparation of lead zirconate precursor solution:

[0060] Dissolve the lead acetate in the ethylene glycol methyl ether, and heat and stir at 60°C until clear to obtain solution A; add the zirconium n-propylate to the solution A after cooling to room temperature, and stir to obtain the lead zirconate precursor solution;

[0061] The concentration of the lead zirconate precursor solution in step II is 0.3 mol / L;

[0062] III. Preparation of antiferroelectric composite film:

[0063] Spin-coat 1 layer of the Ta2O5 precursor solution and 4 layers of the lead zirconate precursor solution on the substrate in sequence, then dry the wet film on a flat heater and place it in a rapid annealing furnace for rapid annealing to obtain the antiferroelectric composite film (1Ta2O5-PZO) with high polarization intensity and low leakage current density;

[0064] The substrate in step III is a Si substrate;

[0065] The temperature for drying in step III is 420°C, and the time is 10 min;

[0066] The temperature for annealing in step III is 750°C, and the time is 10 min;

[0067] The thickness of the tantalum pentoxide layer (Ta2O5) in the antiferroelectric composite film with high polarization intensity and low leakage current density in step III is 10 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0068] Example 2: An antiferroelectric composite film with high polarization intensity and low leakage current density, which is composed of a tantalum pentoxide layer (Ta2O5) and a lead zirconate layer (PbZrO3), and is prepared according to the following steps:

[0069] I. Preparation of Ta2O5 precursor solution:

[0070] Dissolve the tantalum ethoxide in the ethylene glycol methyl ether solution, and stir at room temperature to obtain the Ta2O5 precursor solution;

[0071] The concentration of the Ta2O5 precursor solution in step one is 0.025 mol / L;

[0072] II. Preparation of lead zirconate precursor solution:

[0073] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir at 60℃ until clear to obtain solution A; after cooling to room temperature, add zirconium n-propylate to solution A, stir to obtain a lead zirconate precursor solution;

[0074] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0075] III. Preparation of antiferroelectric composite film:

[0076] Spin 2 layers of Ta2O5 precursor solution and 4 layers of lead zirconate precursor solution on the substrate in sequence, then dry the wet film on a flat heater and place it in a rapid annealing furnace for rapid annealing to obtain an antiferroelectric composite film (2Ta2O5-PZO) with high polarization intensity and low leakage current density;

[0077] The substrate in step three is a Si substrate;

[0078] The temperature of the drying in step three is 420℃, and the time is 10 min;

[0079] The temperature of the annealing in step three is 750℃, and the time is 10 min;

[0080] The thickness of the tantalum pentoxide layer (Ta2O5) in the antiferroelectric composite film with high polarization intensity and low leakage current density in step three is 20 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0081] Example 3: An antiferroelectric composite film with high polarization intensity and low leakage current density, the antiferroelectric composite film is a lead zirconate layer (PbZrO3), and the preparation method is specifically completed by the following steps:

[0082] I. Preparation of lead zirconate precursor solution:

[0083] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir at 60℃ until clear to obtain solution A; after cooling to room temperature, add zirconium n-propylate to solution A, stir to obtain a lead zirconate precursor solution;

[0084] The concentration of the lead zirconate precursor solution in step one is 0.3 mol / L;

[0085] II. Preparation of antiferroelectric composite film:

[0086] Spin-coating 4 layers of lead zirconate precursor solution on a substrate, then drying the wet film on a flat heater and then placing it in a rapid annealing furnace for rapid annealing to obtain a high-polarization strength and low leakage current density antiferroelectric composite film (PZO);

[0087] The substrate in step two is a Si substrate;

[0088] The temperature for drying in step two is 420℃ and the time is 10 min;

[0089] The temperature for annealing in step two is 750℃ and the time is 10 min;

[0090] The thickness of the lead zirconate layer (PbZrO3) in the high-polarization strength and low leakage current density antiferroelectric composite film in step two is 270 nm.

[0091] Example 4: A high-polarization strength and low leakage current density antiferroelectric composite film, which is composed of a zinc oxide layer (ZnO) and a lead zirconate layer (PbZrO3), is prepared according to the following steps:

[0092] I. Preparation of ZnO precursor solution:

[0093] Dissolve zinc nitrate in ethylene glycol methyl ether solution and stir at 60℃ to obtain a ZnO precursor solution;

[0094] The concentration of the ZnO precursor solution in step one is 0.05 mol / L;

[0095] II. Preparation of lead zirconate precursor solution:

[0096] Dissolve lead acetate in ethylene glycol methyl ether and heat and stir at 60℃ until clear to obtain solution A; after cooling to room temperature, add zirconium n-propylate to solution A and stir to obtain a lead zirconate precursor solution;

[0097] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0098] III. Preparation of antiferroelectric composite film:

[0099] Spin-coat 1 layer of ZnO precursor solution and 4 layers of lead zirconate precursor solution on a substrate in sequence, then dry the wet film on a flat heater and then place it in a rapid annealing furnace for rapid annealing to obtain a high-polarization strength and low leakage current density antiferroelectric composite film (1ZnO-PZO);

[0100] The substrate in step three is a Si substrate;

[0101] The temperature of the drying in step three is 420℃, and the time is 10 min;

[0102] The temperature of the annealing in step three is 750℃, and the time is 10 min;

[0103] The thickness of the zinc oxide layer (ZnO) in the high-polarization and low-leakage antiferroelectric composite film in step three is 15 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0104] Embodiment 5: A high-polarization and low-leakage antiferroelectric composite film, which is composed of a zinc oxide layer (ZnO) and a lead zirconate layer (PbZrO3), and is prepared by the following steps:

[0105] I. Preparation of ZnO precursor solution:

[0106] Dissolve zinc nitrate in ethylene glycol methyl ether solution, and stir at 60℃ to obtain the ZnO precursor solution;

[0107] The concentration of the ZnO precursor solution in step one is 0.05 mol / L;

[0108] II. Preparation of lead zirconate precursor solution:

[0109] Dissolve lead acetate in ethylene glycol methyl ether, and heat and stir at 60℃ until it is clear to obtain solution A; after cooling to room temperature, add zirconium n-propyl alcohol to solution A, and stir to obtain the lead zirconate precursor solution;

[0110] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0111] III. Preparation of antiferroelectric composite film:

[0112] Spin-coat 2 layers of ZnO precursor solution and 4 layers of lead zirconate precursor solution on the substrate in sequence, then dry the wet film on a flat heater, and then place it in a rapid annealing furnace for rapid annealing to obtain the high-polarization and low-leakage antiferroelectric composite film (2ZnO-PZO);

[0113] The substrate in step three is a Si substrate;

[0114] The temperature of the drying in step three is 420℃, and the time is 10 min;

[0115] The temperature of the annealing in step three is 750℃, and the time is 10 min;

[0116] The thickness of the zinc oxide layer (ZnO) in the high-polarization and low-leakage current density antiferroelectric composite film in step three is 30 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0117] Embodiment 6: A high-polarization and low-leakage current density antiferroelectric composite film, which is composed of a zinc oxide layer (ZnO) and a lead zirconate layer (PbZrO3), and is prepared by the following steps:

[0118] I. Preparation of ZnO precursor solution:

[0119] Dissolve zinc nitrate in ethylene glycol methyl ether solution, and stir at 60°C to obtain a ZnO precursor solution;

[0120] The concentration of the ZnO precursor solution in step one is 0.05 mol / L;

[0121] II. Preparation of lead zirconate precursor solution:

[0122] Dissolve lead acetate in ethylene glycol methyl ether, and heat and stir at 60°C until clear to obtain solution A; after cooling to room temperature, add zirconium n-propylate to solution A and stir to obtain a lead zirconate precursor solution;

[0123] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0124] III. Preparation of antiferroelectric composite film:

[0125] Spin-coat 3 layers of ZnO precursor solution and 4 layers of lead zirconate precursor solution on a substrate in sequence, then dry the wet film on a flat heater and then place it in a rapid annealing furnace for rapid annealing to obtain a high-polarization and low-leakage current density antiferroelectric composite film (3ZnO-PZO);

[0126] The substrate in step three is a Si substrate;

[0127] The drying temperature in step three is 420°C, and the time is 10 min;

[0128] The annealing temperature in step three is 750°C, and the time is 10 min;

[0129] The thickness of the zinc oxide layer (ZnO) in the high-polarization and low-leakage current density antiferroelectric composite film in step three is 45 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0130] Embodiment 7: A high-polarization and low-leakage current density antiferroelectric composite thin film, which is composed of a zinc oxide layer (ZnO) and a lead zirconate layer (PbZrO3), and the preparation method is specifically completed by the following steps:

[0131] I. Preparation of a ZnO precursor solution:

[0132] Dissolve zinc nitrate in ethylene glycol methyl ether solution, and stir at 60℃ to obtain a ZnO precursor solution;

[0133] The concentration of the ZnO precursor solution in step one is 0.05 mol / L;

[0134] II. Preparation of a lead zirconate precursor solution:

[0135] Dissolve lead acetate in ethylene glycol methyl ether, and heat and stir at 60℃ until clear to obtain solution A; after cooling to room temperature, add zirconium n-propyl alcohol to solution A, and stir to obtain a lead zirconate precursor solution;

[0136] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0137] III. Preparation of an antiferroelectric composite thin film:

[0138] Spin-coat 4 layers of the ZnO precursor solution and 4 layers of the lead zirconate precursor solution on a substrate in sequence, then dry the wet film on a flat heater and then place it in a rapid annealing furnace for rapid annealing to obtain a high-polarization and low-leakage current density antiferroelectric composite thin film (4ZnO-PZO);

[0139] The substrate in step three is a Si substrate;

[0140] The temperature of the drying in step three is 420℃, and the time is 10 min;

[0141] The temperature of the annealing in step three is 750℃, and the time is 10 min;

[0142] In the high-polarization and low-leakage current density antiferroelectric composite thin film in step three, the thickness of the zinc oxide layer (ZnO) is 60 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0143] Embodiment 8: A high-polarization and low-leakage current density antiferroelectric composite thin film, which is composed of a zirconium oxide layer (ZrO2) and a lead zirconate layer (PbZrO3), and the preparation method is specifically completed by the following steps:

[0144] I. Preparation of a ZrO2 precursor solution:

[0145] Dissolving zirconium n-propoxide in ethylene glycol methyl ether solution, stirring at room temperature to obtain ZrO2 precursor solution;

[0146] The concentration of the ZrO2 precursor solution in step one is 0.05 mol / L;

[0147] II. Preparation of lead zirconate precursor solution:

[0148] Dissolving lead acetate in ethylene glycol methyl ether, stirring at 60℃ until clear to obtain solution A; adding zirconium n-propoxide in solution A after cooling to room temperature, stirring to obtain lead zirconate precursor solution;

[0149] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0150] III. Preparation of antiferroelectric composite film:

[0151] In sequence, spin-coating 1 layer of ZrO2 precursor solution and 4 layers of lead zirconate precursor solution on the substrate, then drying the wet film on a flat heater and then placing it in a rapid annealing furnace for rapid annealing to obtain antiferroelectric composite film (1ZrO2-PZO) with high polarization strength and low leakage current density;

[0152] The substrate in step three is Si substrate;

[0153] The temperature of the drying in step three is 420℃, and the time is 10 min;

[0154] The temperature of the annealing in step three is 750℃, and the time is 10 min;

[0155] The thickness of zirconium oxide (ZrO2) in the antiferroelectric composite film with high polarization strength and low leakage current density in step three is 10 nm, and the thickness of lead zirconate layer (PbZrO3) is 270 nm.

[0156] Example 9: An antiferroelectric composite film with high polarization strength and low leakage current density, which is composed of zirconium oxide (ZrO2) and lead zirconate layer (PbZrO3), and the preparation method is completed according to the following steps:

[0157] I. Preparation of ZrO2 precursor solution:

[0158] Dissolving zirconium n-propoxide in ethylene glycol methyl ether solution, stirring at room temperature to obtain ZrO2 precursor solution;

[0159] The concentration of the ZrO2 precursor solution in step one is 0.05 mol / L;

[0160] II. Preparation of lead zirconate precursor solution:

[0161] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir at 60°C until clear to obtain solution A; after cooling to room temperature, add zirconium n-propoxide to solution A and stir to obtain a lead zirconate precursor solution;

[0162] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0163] III. Preparation of a antiferroelectric composite film:

[0164] Spin 4 layers of ZrO2 precursor solution and 4 layers of lead zirconate precursor solution on a substrate in sequence, then dry the wet film on a flat heater and then place it in a rapid annealing furnace for rapid annealing to obtain an antiferroelectric composite film (4ZrO2-PZO) with high polarization strength and low leakage current density;

[0165] The substrate in step three is a Si substrate;

[0166] The temperature of the drying in step three is 420°C and the time is 10 min;

[0167] The temperature of the annealing in step three is 750°C and the time is 10 min;

[0168] The thickness of the zirconium oxide (ZrO2) in the antiferroelectric composite film with high polarization strength and low leakage current density in step three is 40 nm and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0169] Comparative Example 1: An antiferroelectric composite film with high polarization strength and low leakage current density, which is composed of zirconium oxide (ZrO2) and a lead zirconate layer (PbZrO3), is prepared according to the following steps:

[0170] I. Preparation of a ZrO2 precursor solution:

[0171] Dissolve zirconium n-propoxide in ethylene glycol methyl ether and stir at room temperature to obtain a ZrO2 precursor solution;

[0172] The concentration of the ZrO2 precursor solution in step one is 0.05 mol / L;

[0173] II. Preparation of a lead zirconate precursor solution:

[0174] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir at 60°C until clear to obtain solution A; after cooling to room temperature, add zirconium n-propoxide to solution A and stir to obtain a lead zirconate precursor solution;

[0175] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0176] III. Preparation of antiferroelectric composite film:

[0177] spin-coating 2 layers of ZrO2 precursor solution and 4 layers of lead zirconate precursor solution on the substrate in sequence, then drying the wet film on a flat heater and then placing it in a rapid annealing furnace for rapid annealing to obtain an antiferroelectric composite film (2ZrO2-PZO) with high polarization strength and low leakage current density;

[0178] The substrate in step three is a Si substrate;

[0179] The temperature of the drying in step three is 420℃ and the time is 10 min;

[0180] The temperature of the annealing in step three is 750℃ and the time is 10 min;

[0181] The thickness of the zirconium oxide (ZrO2) in the antiferroelectric composite film with high polarization strength and low leakage current density in step three is 20 nm and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0182] Comparative Example 2: An antiferroelectric composite film with high polarization strength and low leakage current density, which is composed of zirconium oxide (ZrO2) and a lead zirconate layer (PbZrO3), is prepared according to the following steps:

[0183] I. Preparation of ZrO2 precursor solution:

[0184] Dissolve zirconium n-propylate in ethylene glycol methyl ether solution, stir at room temperature to obtain a ZrO2 precursor solution;

[0185] The concentration of the ZrO2 precursor solution in step one is 0.05 mol / L;

[0186] II. Preparation of lead zirconate precursor solution:

[0187] Dissolve lead acetate in ethylene glycol methyl ether, heat and stir at 60℃ until clear to obtain solution A; add zirconium n-propylate to solution A after cooling to room temperature, stir to obtain a lead zirconate precursor solution;

[0188] The concentration of the lead zirconate precursor solution in step two is 0.3 mol / L;

[0189] III. Preparation of antiferroelectric composite film:

[0190] Three layers of ZrO2 precursor solution and four layers of lead zirconate precursor solution were spin-coated on a substrate in sequence. The wet film was then dried on a flat heater and then placed in a rapid annealing furnace for rapid annealing to obtain an antiferroelectric composite film (3ZrO2-PZO) with high polarization strength and low leakage current density.

[0191] The substrate described in step 3 is a Si substrate;

[0192] The drying temperature in step 3 is 420°C and the drying time is 10 minutes;

[0193] The annealing temperature in step 3 is 750°C and the time is 10 minutes;

[0194] In the antiferroelectric composite thin film with high polarization strength and low leakage current density described in step 3, the thickness of the zirconium oxide (ZrO2) layer is 30 nm, and the thickness of the lead zirconate layer (PbZrO3) is 270 nm.

[0195] Figure 1 Schematic diagram of the structure of an antiferroelectric composite film with high polarization strength and low leakage current density in the present invention;

[0196] from Figure 1 It can be seen that the composite film grows on the substrate and consists of two parts: the functional layer and the lead zirconate layer.

[0197] Figure 2 XRD comparison spectra of the antiferroelectric composite films with high polarization strength and low leakage current density prepared in Examples 1 to 3;

[0198] Figure 3 XRD comparison spectra of the antiferroelectric composite films with high polarization strength and low leakage current density prepared in Examples 3 to 7;

[0199] Figure 4 XRD comparison spectra of the antiferroelectric composite films with high polarization intensity and low leakage current density prepared in Examples 3, 8, 9, Comparative Example 1 and Comparative Example 2;

[0200] from Figures 2 to 4 It can be seen that there are obvious characteristic diffraction peaks in the film sample, and the film is in good crystallization condition.

[0201] Figure 5 The hysteresis loop diagrams of the antiferroelectric composite films with high polarization intensity and low leakage current density prepared in Examples 1 to 3;

[0202] from Figure 5 It can be seen that after the introduction of the Ta2O5 functional layer, the antiferroelectricity of the inorganic film is weakened and the polarization strength of the film is improved. The polarization strength of the Ta2O5-PZO composite film can reach 140μC / cm 2 .

[0203] Figure 6 The hysteresis loop of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Example 4-7;

[0204] From Figure 6 It can be seen from the above table that after the introduction of ZnO functional layer, the polarization loss of inorganic thin film is greatly reduced, the hysteresis loop becomes thin, and the polarization intensity of 2ZnO-PZO composite thin film is close to 250 μC / cm 2 .

[0205] Figure 7 The hysteresis loop of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Example 8, 9, Comparative Example 1 and Comparative Example 2;

[0206] From Figure 7 It can be seen from the above table that after the introduction of ZrO2 functional layer, the antiferroelectricity of inorganic thin film is weakened, the hysteresis loop becomes thin, and the polarization intensity of 2ZrO2-PZO composite thin film is close to 120 μC / cm 2 .

[0207] Figure 8 The leakage current graph of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Example 3, 4, 5, 7;

[0208] From Figure 8 It can be seen from the above table that after the introduction of ZnO functional layer, the leakage current of inorganic thin film does not change much, and is maintained at 10 -6 A or below.

[0209] Figure 9 The leakage current graph of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Example 8, 9 and Comparative Example 1;

[0210] From Figure 9 It can be seen from the above table that after the introduction of ZrO2 functional layer, the leakage current of inorganic thin film is greatly reduced. Among them, the leakage current of 2ZrO2-PZO is close to 10 -9 A.

[0211] Figure 10 The leakage current graph of the antiferroelectric composite thin film with high polarization intensity and low leakage current density prepared in Example 1-2;

[0212] From Figure 10 It can be seen from the above table that after the introduction of Ta2O5 functional layer, the leakage current of inorganic thin film shows an upward trend, and the insulation performance is slightly deteriorated.

[0213] The above merely describes preferred embodiments of the present application, and the skilled in the art can make appropriate changes and modifications to the above embodiments, and the present application is not limited to the above specific embodiments. Some modifications and changes of the present application should fall within the protection scope of the claims of the present application.

Claims

1. A method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density, characterized in that The antiferroelectric composite film is composed of a functional layer and a lead zirconate layer; the functional layer is one or more of tantalum pentoxide, zinc oxide or zirconium oxide; the thickness of the functional layer is 10nm to 60nm, and the thickness of the lead zirconate layer is 260nm to 300nm; The preparation method is specifically completed according to the following steps:

1. Preparation of functional layer precursor solution: The functional layer precursor solution is one or more of a Ta2O5 precursor solution, a ZnO precursor solution, and a ZrO2 precursor solution, and the preparation method is as follows: ① Dissolve tantalum ethoxide in ethylene glycol methyl ether solution and stir at room temperature to obtain Ta2O5 precursor solution; ② Dissolve zinc nitrate in ethylene glycol methyl ether solution, heat and stir to obtain ZnO precursor solution; ③ Dissolve zirconium n-propoxide in ethylene glycol methyl ether solution and stir at room temperature to obtain a ZrO2 precursor solution; 2. Preparation of lead zirconate precursor solution: Lead acetate is dissolved in ethylene glycol methyl ether, heated and stirred until clear to obtain solution A; after cooling to room temperature, zirconium n-propoxide is added to solution A and stirred to obtain a lead zirconate precursor solution; 3. Preparation of antiferroelectric composite thin films: A functional layer precursor solution and a lead zirconate precursor solution are sequentially spin-coated on a substrate, and the wet film is then dried on a flat heater and then placed in a rapid annealing furnace for rapid annealing to obtain an antiferroelectric composite film with high polarization strength and low leakage current density. The substrate described in step three is a mica or Si substrate.

2. The method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density according to claim 1, characterized in that The concentration of the Ta2O5 precursor solution described in step 1① is 0.02 mol / L~0.03 mol / L; the concentration of the ZnO precursor solution described in step 1② is 0.04 mol / L~0.06 mol / L; the concentration of the ZrO2 precursor solution described in step 1③ is 0.04 mol / L~0.06 mol / L.

3. The method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density according to claim 1, characterized in that The concentration of the lead zirconate precursor solution in step 2 is 0.2 mol / L to 0.4 mol / L.

4. The method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density according to claim 1, characterized in that The temperature of heating and stirring in step 1② is 60℃~70℃; in step 2, heating and stirring at 60℃ until clear.

5. The method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density according to claim 1, characterized in that The spin coating process described in step 3 is: first spin coating at 1000 rpm, and then spin coating at 3500 rpm.

6. The method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density according to claim 1, characterized in that The drying temperature in step 3 is 400° C. to 430° C., and the drying time is 6 min to 10 min.

7. The method for preparing an antiferroelectric composite film with high polarization strength and low leakage current density according to claim 1, characterized in that The annealing temperature in step 3 is 740° C. to 760° C., and the annealing time is 5 min to 10 min.

8. Use of an antiferroelectric composite film with high polarization strength and low leakage current density prepared by the preparation method according to claim 1, characterized in that The invention discloses an antiferroelectric composite film with high polarization intensity and low leakage current density and is applied in inorganic film capacitors or memories.

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