Quaternary amorphous metal oxide thin film with ultrahigh dielectric and low leakage current as well as preparation and application of quaternary amorphous metal oxide thin film
By preparing quaternary amorphous metal oxide thin films by mixing metal oxides with different valence states and ionic radii, the problem of large leakage current in dielectric materials during size reduction was solved, achieving the effect of high dielectric constant and low leakage current.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- SOUTH CHINA UNIV OF TECH
- Filing Date
- 2025-12-10
- Publication Date
- 2026-04-14
AI Technical Summary
Existing dielectric materials are prone to large leakage currents during the size reduction process, and the dielectric constant of traditional SiO2 dielectric layers is small, which cannot meet the needs of future electronic devices.
Four quaternary amorphous metal oxide thin films were prepared by mixing four metal oxides with different valence states and large differences in ionic radii: ZrOx, AlOx, MgO, and YOx. The 5s orbitals of Zr4+ and Y3+ formed good bonds with other ions, and Al3+ and Mg2+ were embedded in the intermolecular voids, thereby increasing the number of molecules and the charge storage capacity per unit volume.
It achieves a dielectric constant between 40 and 60 and a leakage current of only 10⁻⁹ A, meeting the requirements of electronic devices with high dielectric constant and low leakage current.
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Figure CN121865859A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of electronic technology, specifically relating to a quaternary amorphous metal oxide thin film with ultra-high dielectric and low leakage current, and its preparation and application. Background Technology
[0002] Dielectric thin films play a crucial role in the development of the new technological era. They are commonly used in the fabrication of capacitors, requiring high resistivity and a large dielectric constant. Many electronic devices, such as supercapacitors, information storage devices, biomimetic neuromorphic devices, and thin-film transistors in displays, rely heavily on dielectric layers. High dielectric constant, low loss, and excellent high-temperature resistance have become the three major performance indicators for advanced dielectric layers. With the rapid development of electronic devices, dielectric layers face challenges such as low-temperature fabrication, miniaturization, and low leakage current density. Traditional SiO2 dielectric layers, due to their very low dielectric constant, are prone to large leakage currents due to tunneling effects as their size shrinks, which is not in line with future development trends. Therefore, efforts are now focused on fabricating new high-dielectric materials, such as metal oxides, which typically achieve a dielectric constant of 20, while crystalline titanium oxide thin films can reach a dielectric constant of nearly 40. However, because of their crystalline state, conductive channels are easily formed, resulting in large leakage currents, which does not meet the requirements of common electronic devices for dielectric layers. Summary of the Invention
[0003] To address the shortcomings and deficiencies of existing technologies, the primary objective of this invention is to provide a method for preparing quaternary amorphous metal oxide thin films with ultra-high dielectric strength and low leakage current. This invention utilizes four metal oxide dielectric materials (ZrO4, ZrO2 ... x AlO x MgO, YO x Quaternary metal oxide thin films were prepared by mixing. Typically, the dielectric constant of a metal oxide is determined by the dipole moment within the molecule and its ability to store charge. According to the following polarizability formula, the dipole moment increases with the number of molecules per unit volume.
[0004] Therefore, by mixing four metal oxides with different atomic radii, cations with smaller atomic radii, such as Al, can be made more homogeneous. 3+ and Mg 2+ It can be embedded in the gaps between molecules, thereby increasing the number of molecules per unit volume. To avoid an increase in film defects due to the small overlap of electron p orbitals between different cations, this invention selects Zr... 4+ and Y 3+ The ions possess circular 5s orbitals, enabling them to form better bonds with other embedded ions, thereby improving film quality and controlling leakage current. Furthermore, the Zr ions selected in this invention have a larger ionic radius.4+ and Y 3+ And Al with smaller ionic radius 3+ and Mg 2+ Cations with similar ionic radii have different valence states, so the potential difference between them can increase the ability of the thin film to store charge, thereby increasing the dielectric constant.
[0005] Another object of the present invention is to provide a quaternary amorphous metal oxide thin film obtained by the above preparation method.
[0006] Another object of the present invention is to provide an application of the above-mentioned quaternary amorphous metal oxide thin film.
[0007] To achieve this objective, the present invention adopts the following technical solution: In a first aspect, the present invention provides a method for preparing a quaternary amorphous metal oxide thin film, comprising the following steps: (1) Place Al 3+ Mg 2+ Zr 4+ and Y 3+ The corresponding inorganic metal salt is dissolved in an organic solvent to obtain a precursor solution; (2) Spin-coat the precursor liquid onto the substrate, pre-anneal it, repeat the spin-coat-pre-annealing process 1 to 3 times, and then perform thermal annealing to obtain a quaternary metal oxide dielectric film.
[0008] Preferably, the Al in step (1) 3+ Mg 2+ Zr 4+ and Y 3+ The corresponding inorganic metal salts include aluminum nitrate, zirconium nitrate, magnesium acetate, and yttrium nitrate.
[0009] Preferably, the Al in step (1) 3+ Mg 2+ Zr 4+ and Y 3+ The molar ratio is (1±0.1):(1±0.1):(1±0.1):(1±0.1).
[0010] Preferably, the organic solvent in step (1) includes ethylene glycol methyl ether.
[0011] Preferably, the total concentration of inorganic metal salts in the organic solvent in step (1) is 0.8 to 1.0 mol / L.
[0012] Preferably, the substrate in step (2) comprises at least one of glass, quartz, monocrystalline silicon, sapphire, and plastic.
[0013] Preferably, the spin coating process conditions in step (2) are: spin coating speed of 3000-6000 rpm and spin coating time of 30-50 s per spin.
[0014] Preferably, the pre-annealing temperature in step (2) is 130-150 °C; the time is preferably 10-20 min.
[0015] Preferably, the temperature of the heat annealing in step (2) is 300-500 °C and the time is 1.5-2 h.
[0016] Secondly, the present invention provides a quaternary amorphous metal oxide thin film obtained by the above preparation method.
[0017] Thirdly, the present invention provides the application of the above-mentioned quaternary amorphous metal oxide thin film in capacitors.
[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects: This invention utilizes organic solvents, simplifying impurity removal and requiring low annealing temperatures. Compared to existing metal oxide dielectric materials, this quaternary metal oxide dielectric layer exhibits superior dielectric properties, with a dielectric constant between 40 and 60, offering significant potential for its development in the field of dielectric materials. Furthermore, its leakage current is only 10 N / L. -9 A. Attached Figure Description
[0019] Figure 1 A schematic diagram of ions with different atomic radii filling the voids.
[0020] Figure 2 (a) shows the orbital distribution of the Y atom; (b) shows the overlapping portion between the 4p orbitals; and (c) shows the overlapping portion of the 5s orbitals.
[0021] Figure 3 The values for (a) current and (b) capacitance obtained in Example 1 are shown.
[0022] Figure 4 The values for (a) current and (b) capacitance obtained in Example 2 are shown.
[0023] Figure 5 The values for (a) current and (b) capacitance obtained from the test in Comparative Example 1 are shown.
[0024] Figure 6 The values for (a) current and (b) capacitance obtained from the tests in Comparative Example 2 are shown.
[0025] All of the above capacitance values were measured at a frequency of 1 kHz. Detailed Implementation
[0026] The present invention will be further described in detail below with reference to the embodiments and accompanying drawings, but the implementation of the present invention is not limited thereto.
[0027] Unless otherwise specified in the embodiments of this invention, the conditions shall be performed according to conventional conditions or conditions recommended by the manufacturer. All raw materials and reagents used, unless otherwise specified, are commercially available conventional products.
[0028] This invention calculates the dielectric constant based on the following relationship:
[0029] in C For capacitors, k Where is the dielectric constant. ε 0 The vacuum permittivity is 8.85 × 10⁻⁶. -12 F / m), S For electrode area, d The dielectric layer thickness is [value missing].
[0030] Example 1 This embodiment describes a method for preparing an ultra-high dielectric quaternary amorphous metal oxide thin film. The specific steps for preparing the precursor solution and the thin film are as follows: (1) Select aluminum nitrate, zirconium nitrate, magnesium acetate and yttrium nitrate, dissolve them in equimolar amounts in ethylene glycol methyl ether solvent, the total concentration of the solution is 1.0 mol / L, and after stirring the prepared solution on a magnetic stirrer for one day, a transparent and clear precursor solution is obtained.
[0031] (2) The organic precursor solution was spin-coated onto the glass substrate at a high speed of 5000 rpm for 30 seconds. After spin-coating, annealing was performed at a pre-annealing temperature of 150°C for 10 minutes. The organic precursor solution was then spin-coated onto the organic precursor on the glass substrate and pre-annealed. This operation was repeated twice (the process parameters for spin-coating and pre-annealing were the same as described above). Annealing was then performed at a temperature of 400°C for 1.5 hours to obtain a quaternary metal oxide dielectric film.
[0032] (3) Test results: Leakage current does not exceed 2.40 × 10 -9 A, leakage current density does not exceed 1.63 × 10 -6 A / cm 2 The capacitance is not less than 2.30 × 10 -10 F, calculated using the formula, has an average dielectric constant of 56.1 at a frequency of 1 kHz.
[0033] Example 2 This embodiment describes a method for preparing an ultra-high dielectric quaternary amorphous metal oxide thin film. The specific steps for preparing the precursor solution and the thin film are as follows: (1) Select aluminum nitrate, zirconium nitrate, magnesium acetate and yttrium nitrate, dissolve them in equimolar amounts in ethylene glycol methyl ether solvent, the total concentration of the solution is 1.0 mol / L, and after stirring the prepared solution on a magnetic stirrer for one day, a transparent and clear precursor solution is obtained.
[0034] (2) The organic precursor solution was spin-coated onto the glass substrate at a high speed of 5000 rpm for 30 seconds. After spin-coating, annealing was performed at a pre-annealing temperature of 150°C for 10 minutes. The organic precursor solution was then spin-coated onto the organic precursor on the glass substrate and pre-annealed. This operation was repeated twice (the process parameters for spin-coating and pre-annealing were the same as described above). Annealing was then performed at a temperature of 500°C for 1.5 hours to obtain a quaternary metal oxide dielectric film.
[0035] Test results: Leakage current does not exceed 3.06 × 10⁻⁶ -9 A, leakage current density does not exceed 2.08 × 10 -6 A / cm 2 The capacitance is not less than 1.76 × 10⁻⁶. -10 F, calculated using the formula, has a dielectric constant of 42.2 at a frequency of 1kHz.
[0036] Comparative Example 1 The preparation method of other elemental quaternary amorphous metal oxide thin films in this embodiment, specifically the precursor solution and film preparation steps are as follows: (1) Select aluminum nitrate, zirconium nitrate, magnesium acetate and yttrium nitrate, dissolve them in ethylene glycol methyl ether solvent in a molar ratio of 1:1:2:2, and the total concentration of the solution is 1.0 mol / L. After the prepared solution is stirred on a magnetic stirrer for one day, a transparent and clear precursor solution is obtained.
[0037] (2) The organic precursor solution was spin-coated onto the glass substrate at a high speed of 5000 rpm for 30 seconds. After spin-coating, annealing was performed at a pre-annealing temperature of 150°C for 10 minutes. The organic precursor solution was then spin-coated onto the organic precursor on the glass substrate and pre-annealed. This operation was repeated twice (the process parameters for spin-coating and pre-annealing were the same as described above). Annealing was then performed at a temperature of 400°C for 1.5 hours to obtain a quaternary metal oxide dielectric film.
[0038] (3) Test results: Leakage current does not exceed 7.15×10 -9 A, leakage current density does not exceed 1.12 × 10 -7 A / cm2 The capacitance is not less than 2.3 × 10⁻⁶. -10 F, calculated using the formula, has an average dielectric constant of only 9.4 at a frequency of 1kHz.
[0039] Comparative Example 2 The preparation method of other elemental quaternary amorphous metal oxide thin films in this embodiment, specifically the precursor solution and film preparation steps are as follows: (1) Select aluminum nitrate, zirconium nitrate, hafnium chloride and yttrium nitrate, dissolve them in equimolar amounts in ethylene glycol methyl ether solvent, the total concentration of the solution is 1.0 mol / L, and after the prepared solution is stirred on a magnetic stirrer for one day, a transparent and clear precursor solution is obtained.
[0040] (2) The organic precursor solution was spin-coated onto the glass substrate at a high speed of 5000 rpm for 30 seconds. After spin-coating, annealing was performed at a pre-annealing temperature of 150°C for 10 minutes. The organic precursor solution was then spin-coated onto the organic precursor on the glass substrate and pre-annealed. This operation was repeated twice (the process parameters for spin-coating and pre-annealing were the same as described above). Annealing was then performed at a temperature of 400°C for 1.5 hours to obtain a quaternary metal oxide dielectric film.
[0041] (3) Test results: Leakage current does not exceed 8.5×10 -7 A, leakage current density does not exceed 2.24 × 10 -6 A / cm 2 The capacitance is not less than 3.0 × 10 -10 F, calculated using the formula, has an average dielectric constant of only 7.4 at a frequency of 1 kHz.
[0042] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.
Claims
1. A method for preparing a quaternary amorphous metal oxide thin film, characterized in that, Includes the following steps: (1) Place Al 3+ Mg 2+ Zr 4+ and Y 3+ The corresponding inorganic metal salt is dissolved in an organic solvent to obtain a precursor solution; (2) Spin-coat the precursor liquid onto the substrate, pre-anneal it, repeat the spin-coat-pre-annealing process 1 to 3 times, and then perform thermal annealing to obtain a quaternary metal oxide dielectric film.
2. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, Step (1) Al 3+ Mg 2+ Zr 4+ and Y 3+ The molar ratio is (1±0.1):(1±0.1):(1±0.1):(1±0.1).
3. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, Step (1) Al 3+ Mg 2+ Zr 4+ and Y 3+ The corresponding inorganic metal salts include aluminum nitrate, zirconium nitrate, magnesium acetate, and yttrium nitrate.
4. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, The organic solvent in step (1) includes ethylene glycol methyl ether; And / or, the total concentration of inorganic metal salts in the organic solvent of step (1) is 0.8 to 1.0 mol / L.
5. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, The spin coating process conditions in step (2) are: spin coating speed of 3000-6000 rpm and spin coating time of 30-50 s per spin.
6. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, The pre-annealing temperature in step (2) is 130-150 °C; the preferred time is 10-20 min.
7. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, The temperature of the heat annealing in step (2) is 300-500 °C; the time is 1.5-2 h.
8. The method for preparing a quaternary amorphous metal oxide thin film according to claim 1, characterized in that, The substrate in step (2) includes at least one of glass, quartz, monocrystalline silicon, sapphire, and plastic.
9. A quaternary amorphous metal oxide thin film obtained by the preparation method according to any one of claims 1 to 8.
10. The application of the quaternary amorphous metal oxide thin film according to claim 9 in a capacitor.