A method for preparing PZT thin films at low temperature
By mixing precursor solutions from lead, zirconium, and titanium sources and annealing at 450°C, the compatibility issue between high-temperature PZT thin film preparation and silicon-based CMOS circuits was resolved, enabling the low-temperature preparation of high-performance PZT thin films.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- POLYMER ELECTRO-OPTICS (HANGZHOU) TECH CO LTD
- Filing Date
- 2023-07-06
- Publication Date
- 2026-07-17
AI Technical Summary
The preparation of PZT thin films in the prior art requires high-temperature annealing, which leads to incompatibility with silicon-based CMOS circuits and limits their application in microelectromechanical systems.
A precursor solution was formed by mixing lead, zirconium, and titanium sources with an oxidant and heating the mixture. The solution was then pyrolyzed and annealed at 450°C to prepare PZT thin films.
Low-temperature preparation of PZT thin films was achieved, simplifying the process steps, reducing costs, and maintaining the excellent properties of the films.
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Figure CN116812975B_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of functional materials technology, specifically relating to a method for preparing PZT thin films at low temperature. Background Technology
[0002] Lead zirconate titanate (PZT) films are perovskite-structured metal oxides with excellent piezoelectric, ferroelectric, dielectric, and optoelectronic properties, making them widely used in microelectromechanical systems (MEMS) and a hot research area in functional materials. The fabrication method of PZT films is crucial for device process compatibility; high temperatures can severely damage devices. Typically, high-temperature annealing (around 600℃) is required during PZT film fabrication. For example, PZT films fabricated using the sol-gel method usually require high annealing temperatures (>600℃) (J Mater Sci: Mater Electron, 2023, 34, 1171). However, the maximum temperature that commonly used silicon-based CMOS circuits can withstand is 450℃ (Appl. Phys. Rev. 2021, 8, 041315). The high-temperature fabrication of PZT films has become a bottleneck for their application development, and developing methods for low-temperature PZT film fabrication has become an industry consensus.
[0003] Currently, there are numerous methods for preparing PZT thin films, mainly divided into two categories: physical deposition (PVD) and chemical deposition (CSD). PVD typically requires 550–650℃ to prepare high-performance PZT thin films, while CSD requires 650–750℃. Compared to PVD, CSD is widely used due to its simplicity, low cost, and ability to form large-area films. Low-temperature preparation of PZT thin films using CSD requires consideration of various factors, including seed layer growth, low-temperature annealing techniques, and the preparation of the PZT chemical solution. Regarding annealing techniques, microwave heating, laser-assisted annealing, and UV-assisted annealing have achieved good results; however, these methods are complex to prepare PZT, have poor reproducibility, and pose safety risks. Therefore, providing a simple and efficient method for low-temperature preparation of high-performance PZT thin films is imperative. Summary of the Invention
[0004] The purpose of this invention is to provide a method for preparing PZT thin films at low temperature. Lead, zirconium, and titanium sources are respectively mixed with corresponding fuels and oxidants in a solvent. After reaction, three precursor solutions are obtained. These three precursor solutions are then mixed, pyrolyzed, and annealed to obtain PZT thin films. The annealing temperature only needs to reach 450°C, thus achieving the low-temperature preparation of PZT thin films.
[0005] To achieve the above objectives, the present invention provides the following technical solution:
[0006] A method for preparing PZT thin films at low temperature includes the following steps:
[0007] (1) A lead precursor solution is obtained by mixing a lead source, fuel and oxidant in a solvent and heating the mixture to react. A zirconium precursor solution is obtained by mixing a zirconium source, fuel and oxidant in a solvent and heating the mixture to react. A titanium precursor solution is obtained by mixing a titanium source, fuel and oxidant in a solvent and heating the mixture to react.
[0008] (2) The zirconium precursor solution, titanium precursor solution and lead precursor solution are mixed evenly in sequence to obtain PZT solution, and then PZT film is obtained by pyrolysis and annealing.
[0009] Preferably, in the preparation of the lead precursor solution in step (1), the heating reaction temperature is 100-150°C and the time is 0.5-3.0 h. The lead source includes lead acetate or lead sulfate, the fuel includes tris(hydroxymethyl)methylglycine, urea, acetylacetone, hydrazine, amino acids or sugars, the oxidant includes ammonium nitrate or nitric acid, and the solvent includes ethylene glycol monomethyl ether, methanol, ethanol or isopropanol.
[0010] More preferably, in the preparation of the lead precursor solution, the molar ratio of the lead source, the fuel, and the oxidant is 1 to 2:1:1.
[0011] Preferably, in the preparation of the zirconium precursor solution in step (1), the heating reaction temperature is 100-150°C and the time is 0.5-3.0 h. The zirconium source includes zirconium oxynitrate or zirconium oxyheptanoate, the fuel includes tris(hydroxymethyl)methylglycine, urea, acetylacetone, hydrazine, amino acids or sugars, the oxidant includes ammonium nitrate or nitric acid, and the solvent includes ethylene glycol monomethyl ether, methanol, ethanol or isopropanol.
[0012] More preferably, in the preparation of the zirconium precursor solution, the molar ratio of the zirconium source, the fuel and the oxidant is 1 to 2:1:1.
[0013] Preferably, in the preparation of the titanium precursor solution in step (1), the heating reaction temperature is 100-150°C and the time is 0.5-3.0 h. The titanium source includes tetraisopropyl titanate, tetraethyl titanate or tetrabutyl titanate, the fuel includes tris(hydroxymethyl)methylglycine, urea, acetylacetone, hydrazine, amino acids or sugars, the oxidant includes ammonium nitrate or nitric acid, and the solvent includes ethylene glycol monomethyl ether, methanol, ethanol or isopropanol.
[0014] More preferably, in the preparation of the titanium precursor solution, the molar ratio of the titanium source, the fuel and the oxidant is 1 to 2:1:1.
[0015] Preferably, the molar ratio of lead in the lead precursor solution, zirconium in the zirconium precursor solution and titanium in the titanium precursor solution in step (1) is 1.0 to 1.2:x:(1-x), where x ranges from 0.3 to 0.7.
[0016] Preferably, the pyrolysis temperature in step (2) is 200–300°C; the pyrolysis time is preferably 10–30 min.
[0017] Preferably, the annealing temperature in step (2) is 400-450°C; the annealing time is preferably 0.5-10h.
[0018] The beneficial technical effects of the present invention are as follows:
[0019] The preparation method provided by this invention is simple in steps, low in cost, and can realize the low-temperature preparation of PZT films, and the obtained PZT films have excellent performance. Attached Figure Description
[0020] Figure 1 The image shows the XRD pattern of the PZT thin film obtained in Example 1.
[0021] Figure 2 This is a SEM image of the PZT film obtained in Example 1. Detailed Implementation
[0022] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as a limitation of the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention. It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the present invention.
[0023] Furthermore, regarding the numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, are also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.
[0024] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar to or equivalent to those described herein may be used in the implementation or testing of this invention.
[0025] The terms “include,” “including,” “have,” “contain,” etc., used in this article are all open-ended terms, meaning that they include but are not limited to.
[0026] Example 1
[0027] A method for preparing PZT thin films at low temperature:
[0028] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0029] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0030] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0031] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.52:0.48 (in the order of adding zirconium precursor solution, titanium precursor solution, and lead precursor solution), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0032] 5) The prepared PZT solution was spin-coated, pyrolyzed at 200℃ for 10 min, and annealed at 450℃ for 1.0 h to finally obtain a high-quality PZT film.
[0033] The XRD pattern of the PZT thin film obtained in Example 1 is shown in Figure 1. Figure 1 SEM image (see) Figure 2 .
[0034] from Figure 1 As can be seen from the above, the PZT film prepared by this invention has good crystallinity, which indicates that the obtained PZT film has excellent performance.
[0035] from Figure 2 As can be seen, the PZT thin film prepared by this invention has a uniform thickness, indicating that the quality of the thin film crystal is good.
[0036] Example 2
[0037] A method for preparing PZT thin films at low temperature:
[0038] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 100°C, adjust the stirring speed to 1000 rpm, stir for 3.0 h, cool, and filter to obtain a lead precursor solution.
[0039] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 100°C, adjust the stirring speed to 1000 rpm, stir for 3.0 h, cool, and filter to obtain a zirconium precursor solution.
[0040] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 100°C, adjust the stirring speed to 1000 rpm, stir for 3.0 h, cool, and filter to obtain a titanium precursor solution.
[0041] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.1:0.52:0.48 (the zirconium precursor solution, titanium precursor solution, and lead precursor solution are added in that order), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0042] 5) The prepared PZT solution was spin-coated, pyrolyzed at 200℃ for 10 min, and annealed at 450℃ for 1.0 h to finally obtain a high-quality PZT film.
[0043] Example 3
[0044] A method for preparing PZT thin films at low temperature:
[0045] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 150 °C, adjust the stirring speed to 1000 rpm, stir for 0.5 h, cool, and filter to obtain a lead precursor solution.
[0046] 2) Add zirconium oxynitrate, acetylacetone, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 150 °C, adjust the stirring speed to 1000 rpm, stir for 0.5 h, cool, and filter to obtain a zirconium precursor solution.
[0047] 3) Add tetraisopropyl titanate, acetylacetone, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 150 °C, adjust the stirring speed to 1000 rpm, stir for 0.5 h, cool, and filter to obtain a titanium precursor solution.
[0048] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.52:0.48 (in the order of adding zirconium precursor solution, titanium precursor solution, and lead precursor solution), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0049] 5) The prepared PZT solution was spin-coated, pyrolyzed at 250℃ for 20 min, and annealed at 450℃ for 0.5 h to finally obtain a high-quality PZT film.
[0050] Example 4
[0051] A method for preparing PZT thin films at low temperature:
[0052] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 2:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0053] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a ratio of 2:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0054] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a ratio of 2:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0055] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.52:0.48 (in the order of adding zirconium precursor solution, titanium precursor solution, and lead precursor solution), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0056] 5) The prepared PZT solution was spin-coated, pyrolyzed at 300℃ for 10 min, and annealed at 400℃ for 10 h to finally obtain a high-quality PZT film.
[0057] Example 5
[0058] A method for preparing PZT thin films at low temperature:
[0059] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0060] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0061] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0062] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.52:0.48 (in the order of adding zirconium precursor solution, titanium precursor solution, and lead precursor solution), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0063] 5) The prepared PZT solution was spin-coated, pyrolyzed at 300℃ for 10 min, and annealed at 430℃ for 5.0 h to finally obtain a high-quality PZT film.
[0064] Example 6
[0065] A method for preparing PZT thin films at low temperature:
[0066] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0067] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0068] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0069] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a lead, zirconium, and titanium molar ratio of 1.2:0.5:0.5 (the zirconium precursor solution, titanium precursor solution, and lead precursor solution are added in that order), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0070] 5) The prepared PZT solution was spin-coated, pyrolyzed at 250℃ for 10 min, and annealed at 450℃ for 1 h to finally obtain a high-quality PZT film.
[0071] Example 7
[0072] A method for preparing PZT thin films at low temperature:
[0073] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0074] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0075] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0076] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.4:0.6 (the zirconium precursor solution, titanium precursor solution, and lead precursor solution are added in that order), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0077] 5) The prepared PZT solution was spin-coated, pyrolyzed at 250℃ for 10 min, and annealed at 450℃ for 1 h to finally obtain a high-quality PZT film.
[0078] Example 8
[0079] A method for preparing PZT thin films at low temperature:
[0080] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0081] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0082] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0083] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.3:0.7 (in the order of zirconium precursor solution, titanium precursor solution, and lead precursor solution, respectively), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0084] 5) The prepared PZT solution was spin-coated, pyrolyzed at 250℃ for 10 min, and annealed at 450℃ for 1 h to finally obtain a high-quality PZT film.
[0085] Example 9
[0086] A method for preparing PZT thin films at low temperature:
[0087] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0088] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0089] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0090] 4) The lead, zirconium, and titanium precursor solutions prepared above are mixed together in a molar ratio of lead, zirconium, and titanium of 1.2:0.6:0.4 (the zirconium precursor solution, titanium precursor solution, and lead precursor solution are added in that order), stirred for 0.5 h, and filtered to obtain a stable PZT solution.
[0091] 5) The prepared PZT solution was spin-coated, pyrolyzed at 250℃ for 10 min, and annealed at 450℃ for 1 h to finally obtain a high-quality PZT film.
[0092] Example 10
[0093] A method for preparing PZT thin films at low temperature:
[0094] 1) Add lead nitrate, tris(hydroxymethyl)methylglycine, and ammonium nitrate in a molar ratio of 1:1:1 to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a lead precursor solution.
[0095] 2) Add zirconium oxynitrate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110 °C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a zirconium precursor solution.
[0096] 3) Add tetraisopropyl titanate, urea, and ammonium nitrate in a 1:1:1 ratio to a three-necked round-bottom flask, and add 10 mL of ethylene glycol monomethyl ether. Heat to 110°C, adjust the stirring speed to 1000 rpm, stir for 1.5 h, cool, and filter to obtain a titanium precursor solution.
[0097] 4) Mix the lead, zirconium, and titanium precursor solutions prepared above together in a molar ratio of lead, zirconium, and titanium of 1.2:0.7:0.3 (the zirconium precursor solution, titanium precursor solution, and lead precursor solution are added in that order), stir for 0.5 h, and filter to obtain a stable PZT solution.
[0098] 5) The prepared PZT solution was spin-coated, pyrolyzed at 250℃ for 10 min, and annealed at 450℃ for 1 h to finally obtain a high-quality PZT film.
[0099] The crystallinity and film quality of the PZT films prepared in Examples 2, 3, 4, 5, 6, 7, 8, 9 and 10 are comparable to those in Example 1.
[0100] Comparative Example 1
[0101] A method for preparing PZT thin films at low temperature:
[0102] Compared with Example 1, the difference is that the order of adding the precursor solution in step (4) is adjusted to lead precursor solution, zirconium precursor solution, and titanium precursor solution added in sequence.
[0103] When the order of adding the precursor solution was changed, the resulting PZT solution was unstable and prone to sedimentation, so the subsequent performance testing of the PZT film was not carried out.
[0104] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made by those skilled in the art to the technical solutions of the present invention without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.
Claims
1. A method for preparing PZT thin films at low temperature, characterized in that, Includes the following steps: (1) A lead precursor solution is obtained by mixing a lead source, fuel and oxidant in a solvent and heating the reaction. A zirconium precursor solution is obtained by mixing a zirconium source, fuel and oxidant in a solvent and heating the reaction. A titanium precursor solution is obtained by mixing a titanium source, fuel and oxidant in a solvent and heating the reaction. (2) The zirconium precursor solution, titanium precursor solution and lead precursor solution are mixed evenly in sequence to obtain PZT solution, and then PZT film is obtained by pyrolysis and annealing. In the preparation of the lead precursor solution in step (1), the heating reaction temperature is 100~150℃ and the time is 0.5~3.0 h. The lead source includes lead acetate or lead sulfate, the fuel includes tris(hydroxymethyl)methylglycine, urea, acetylacetone, hydrazine, amino acids or sugars, the oxidant includes ammonium nitrate or nitric acid, and the solvent includes ethylene glycol monomethyl ether, methanol, ethanol or isopropanol. In the preparation of the lead precursor solution, the molar ratio of the lead source, the fuel, and the oxidant is 1~2:1:1; In the preparation of the zirconium precursor solution in step (1), the heating reaction temperature is 100~150℃ and the time is 0.5~3.0h. The zirconium source includes zirconium oxynitrate or zirconium oxyheptanoate, the fuel includes tris(hydroxymethyl)methylglycine, urea, acetylacetone, hydrazine, amino acids or sugars, the oxidant includes ammonium nitrate or nitric acid, and the solvent includes ethylene glycol monomethyl ether, methanol, ethanol or isopropanol. In the preparation of the zirconium precursor solution, the molar ratio of the zirconium source, the fuel, and the oxidant is 1~2:1:1; In the preparation of the titanium precursor solution in step (1), the heating reaction temperature is 100~150℃ and the time is 0.5~3.0h. The titanium source includes tetraisopropyl titanate, tetraethyl titanate or tetrabutyl titanate, the fuel includes tris(hydroxymethyl)methylglycine, urea, acetylacetone, hydrazine, amino acids or sugars, the oxidant includes ammonium nitrate or nitric acid, and the solvent includes ethylene glycol monomethyl ether, methanol, ethanol or isopropanol. In the preparation of the titanium precursor solution, the molar ratio of the titanium source, the fuel, and the oxidant is 1~2:1:1; In step (2), the molar ratio of lead in the lead precursor solution, zirconium in the zirconium precursor solution, and titanium in the titanium precursor solution is 1.0~1.2: x: (1-x), where x ranges from 0.3 to 0.
7. The annealing temperature in step (2) is 400~450℃.
2. The method for preparing PZT thin films at low temperature according to claim 1, characterized in that, The pyrolysis temperature in step (2) is 200~300℃.