CN110767450A

CN110767450A - Thin film capacitor

Info

Publication number: CN110767450A
Application number: CN201811196367.XA
Authority: CN
Inventors: 冯雪; 王志建; 陈颖
Original assignee: Tsinghua University; Institute of Flexible Electronics Technology of THU Zhejiang
Current assignee: Tsinghua University; Institute of Flexible Electronics Technology of THU Zhejiang
Priority date: 2018-07-27
Filing date: 2018-07-27
Publication date: 2020-02-07
Anticipated expiration: 2038-07-27
Also published as: CN110767450B; CN110760801A; CN110760801B; CN110760802B; CN110760802A

Abstract

The invention relates to a film capacitor, which comprises a dielectric film and an electrode layer, wherein the dielectric film comprises a metal substrate, a first metal layer, a second metal oxide layer and a second metal oxide film which are sequentially formed on the metal substrate, and the electrode layer is formed on the second metal oxide film; wherein the material of the first metal layer is the same as the material of the metal substrate; and an alloy layer formed by combining the second metal in the second metal layer with the first metal in the first metal layer is also arranged on the surface of the first metal layer. In the film capacitor, the dielectric film is an energy storage ceramic film, and has high dielectric constant and good energy storage performance. Moreover, the layers in the dielectric thin film are firmly bonded, and the reliability of the dielectric thin film is high. The use of the dielectric thin film in place of a polymer thin film can promote the trend toward miniaturization, light weight, high integration, and multi-functionalization of thin film capacitors.

Description

Thin film capacitor

The application is that the application number is: 201810848153.X, with the filing date of 2018, 7 and 27, entitled: an energy storage thin film and a preparation method thereof.

Technical Field

The invention relates to the field of energy sources, in particular to a film capacitor.

Background

The conventional energy storage ceramic film comprises a substrate and a ceramic film, and generally, the contact area between the ceramic film and the substrate can be increased by increasing the surface roughness of the substrate, so that the bonding force is improved. Further, when the substrate is used as an electrode, the increase in surface roughness can also improve the capacitance of the ceramic thin film. However, the increase of the surface roughness of the electrode increases the defect concentration of the contact surface of the electrode and the ceramic film, so that the breakdown field strength and the energy storage density of the energy storage ceramic film are reduced, and the improvement of the energy storage performance is not facilitated. Therefore, the surface roughness of the electrode is reduced, and the energy storage performance of the energy storage ceramic film is improved. However, the reduction of the surface roughness of the electrode leads to a significant reduction of the bonding force of the electrode to the ceramic thin film, which is also fatal to the energy storage ceramic thin film.

Disclosure of Invention

In view of the above, it is desirable to provide a thin film capacitor having a ceramic energy storage thin film as a dielectric thin film, having a high dielectric constant and capacitance, and capable of realizing miniaturization of the thin film capacitor.

A film capacitor comprises a dielectric film and an electrode layer, wherein the dielectric film comprises a metal substrate, a first metal layer, a second metal oxide layer and a second metal oxide film which are sequentially formed on the metal substrate, and the electrode layer is formed on the second metal oxide film;

wherein the material of the first metal layer is the same as the material of the metal substrate;

and an alloy layer formed by combining the second metal in the second metal layer with the first metal in the first metal layer is also arranged on the surface of the first metal layer.

In one embodiment, the first metal layer and the second metal layer are deposited by a magnetic filtering multi-arc ion plating method, and the alloy layer is formed by a first metal in the first metal layer and a second metal in the second metal layer when the second metal layer is deposited by the magnetic filtering multi-arc ion plating method.

In one embodiment, the surface roughness of the metal substrate is 10nm to 400 nm.

In one embodiment, the thickness of the metal substrate is 6-18 μm; and/or

The surface tension of the metal substrate is more than or equal to 60 dyne.

In one embodiment, the thickness of the first metal layer is 20nm to 40 nm.

In one embodiment, the thickness of the second metal layer is 30nm to 60 nm.

In one embodiment, the alloy layer has a thickness of 5nm to 10 nm.

In one embodiment, the thickness of the second metal oxide layer is 5nm to 10 nm.

In one embodiment, the second metal oxide thin film has a thickness of 25nm to 1.99 μm and a grain size of 30nm to 300 nm.

In one embodiment, the metal substrate comprises a copper foil, the first metal layer comprises a copper layer, the alloy layer comprises a copper titanium alloy layer, the second metal layer comprises a titanium layer, the second metal oxide layer comprises a titanium dioxide layer, and the second metal oxide film comprises a titanium dioxide film.

In the film capacitor, the dielectric film is an energy storage ceramic film, so that the dielectric constant is high and the energy storage performance is good. Moreover, the layers in the dielectric thin film are firmly bonded, and the reliability of the dielectric thin film is high. The use of the dielectric thin film in place of a polymer thin film can promote the trend toward miniaturization, light weight, high integration, and multi-functionalization of thin film capacitors. Meanwhile, the film capacitor has the advantages of no polarity, high insulation resistance, excellent frequency characteristics (wide frequency response), small dielectric loss and the like. The method can be applied to a plurality of industries such as electronics, household appliances, communication, electric power, electrified railways, new energy vehicles, wind power generation, solar power generation and the like. Especially in the signal cross connection part, the thin film capacitor with good frequency characteristic and low dielectric loss of the invention can ensure that the signal is not distorted too much when being transmitted, and has good electrical performance and high reliability.

Drawings

FIG. 1 is a schematic structural diagram of an energy storage ceramic film according to the present invention;

FIG. 2 is a schematic diagram of the magnetic filtering multi-arc ion plating method of the present invention.

In the figure: 1. a vacuum arc source; 2. a lighting device; 3. a visible window; 4. filtering the magnetic field; 5. a focusing magnetic field; 6. a vacuum chamber; 10. a metal substrate; 11. a target material; 12. electrons; 13. a metal droplet; 14. ions; 15. a metal atom; 20. a first metal layer; 30. an alloy layer; 40. a second metal layer; 41. a second metal oxide layer; 42. a second metal oxide film; 50. a ceramic membrane.

Detailed Description

The thin film capacitor provided by the present invention will be further explained below.

The preparation method of the energy storage ceramic film provided by the invention comprises the following steps:

s1, providing a metal substrate;

s2, depositing a first metal prefabricated layer on the metal substrate by using a magnetic filtration multi-arc ion plating method by taking a first metal simple substance as a first target material, wherein the material of the first metal prefabricated layer is the same as that of the metal substrate;

s3, depositing a second metal prefabricated layer on the first metal prefabricated layer by using a magnetic filtration multi-arc ion plating method by taking a second metal simple substance as a second target material, and forming an alloy prefabricated layer between the first metal prefabricated layer and the second metal prefabricated layer while depositing the second metal prefabricated layer, wherein the alloy prefabricated layer is an alloy formed by a first metal and a second metal;

s4, oxidizing the second metal prefabricated layer to form a second metal oxide prefabricated layer on the surface layer of the second metal prefabricated layer;

s5, forming a second metal oxide prefabricated film on the second metal oxide prefabricated layer to obtain a prefabricated energy storage ceramic film;

and S6, performing heat treatment on the prefabricated energy storage ceramic film to obtain the energy storage ceramic film.

In step S1, the metal substrate is used as an electrode, the actual contact area of the first metal prefabricated layer with the electrode is related to the surface roughness of the metal substrate, and the larger the surface roughness is, the larger the actual contact area is, and the larger the capacitance value per unit geometric area is. However, the increase of the roughness of the surface of the metal substrate can increase the defect concentration of the contact surface of the metal substrate and the first metal prefabricated layer, for example, holes are easily generated on the surface of the first metal prefabricated layer, so that the breakdown field strength and the energy storage density of the energy storage ceramic film are reduced, and the improvement of the energy storage performance is not facilitated. Therefore, the surface roughness of the metal substrate is 10 nm-400 nm, which is beneficial to improving the energy storage performance of the ceramic energy storage film.

The metal substrate may be rigid or flexible. Considering that the dielectric constant of the ceramic film is far higher than that of the polymer film, when the metal substrate has flexibility, the energy storage ceramic film can be flexible, so that the ceramic film can be applied to a film capacitor instead of the polymer film, and the film capacitor is developed towards the trends of miniaturization, multifunction, lightness and thinness and the like. Preferably, the thickness of the metal substrate is 6-18 μm, the flexibility is good, and the flexibility of the energy storage ceramic film can be better realized.

The metal substrate is not limited in material, as long as the metal substrate has strong high-temperature oxidation resistance and conductivity, and comprises one of copper foil, titanium foil, silver foil, gold foil, platinum foil, aluminum foil, nickel foil, chromium foil and tin foil, and can also be one of copper alloy, titanium alloy, silver alloy, gold alloy, platinum alloy, aluminum alloy, nickel alloy, chromium alloy and tin alloy.

Considering that copper foil is the most cost-effective metal material in the field of electronics industry, its resistivity is 1.75X 10^-8Omega. m, second only to silver (1.65X 10)^-8Ω · m), a thermal conductivity 401W/(m · K), next to silver (420W/(m · K)), while the price of copper is much lower than that of silver. Secondly, industrial copper foil is mature, the copper foil is divided into rolled copper foil and electrolytic copper foil, and the rolled copper foil and the electrolytic copper foil are subjected to electroplating treatment to prevent oxidation and high-temperature oxidation, and cannot be oxidized when being calcined in air. Therefore, the metal substrate is preferably a copper foil.

The surface tension of the metal substrate is more than or equal to 60 dynes, preferably more than 60 dynes, and the higher the surface tension of the metal substrate is, the stronger the bonding force between the first metal layer and the metal substrate is.

The surface activity can be increased by treating the surface of the metal substrate, thereby increasing the surface tension. Preferably, the treatment method comprises the following steps: firstly heating a metal substrate, setting the temperature to be 100-300 ℃, preserving the heat for 10-30 minutes, then processing the flexible metal substrate by adopting a Hall ion source, wherein the argon flow is 20-50 sccm, the vacuum degree is 2.0 multiplied by 10^-2Pa～6.0×10^-2Pa, the voltage of the Hall ion source is 800V-2000V, the current is 0.5A-2A, and the processing time is 1 minute-10 minutes.

Since the surface roughness of the metal substrate is 10nm to 400nm, the roughness is low, and therefore, the material of the first metal prefabricated layer deposited on the metal substrate in step S2 is the same as the material of the metal substrate. According to the similar compatible principle, the first metal prefabricated layer and the metal substrate are combined more firmly, and the problem of poor combination possibly caused by the reduction of the roughness of the metal substrate is solved.

Considering that the metal substrate is preferably a copper foil, the first metal preform layer is preferably a copper preform layer.

Because the particle energy is lower when traditional magnetron sputtering, sol-gel technology etc. deposit, the bonding force of first metal prefabricated layer and metal substrate is poor. Therefore, the first metal prefabricated layer is formed on the metal substrate in a deposition mode through a magnetic filtering multi-arc ion plating method.

As shown in FIG. 2, the magnetic filtering multi-arc ion plating device of the invention comprises a vacuum arc source 1, a lighting device 2, a visible window 3, a filtering magnetic field 4 and a focusing magnetic field 5, wherein a metal substrate 10 is positioned in a vacuum cavity 6. The magnetic filtration multi-arc ion plating method comprises the steps that electric arcs generated by arcing are combusted on the surface of a target 11 of a first metal simple substance, the target 11 is liquefied to generate ions 14, electrons 12 and metal liquid drops 13, particles (the ions 14 and the electrons 12) with charges are accelerated by an electric field to pass through a filtration magnetic field 4, the charged particles move along magnetic lines of force, and the uncharged metal liquid drops 13 are filtered by the filtration magnetic field 4. After filtering, the pure particles enter the vacuum chamber 6 through the focusing magnetic field 5, and are deposited on the metal substrate 10 by the bias electric field applied to the metal substrate 10. In the whole process, the electrons 12 are gathered and accelerated to form a moving electron cloud, the electron cloud and the ions 14 form a strong electric potential after being separated, the ions 14 are extracted and deposited on the metal substrate 10 together with the electrons 12, the magnetic filtration multi-arc ion plating process is completed, and a first metal prefabricated layer is formed.

In the magnetic filtration multi-arc ion plating process, accelerated electrons 12 continuously impact the surface of the metal substrate 10 to generate metal atoms 15, so that the surface of the metal substrate 10 is cleaned and activated, the surface activity of the metal substrate 10 is enhanced, and the bonding force between the metal substrate 10 and a deposited first metal prefabricated layer is strong. Furthermore, the energy of the particles can be controlled by adjusting the extraction electric field and the bias voltage. Therefore, the particle energy of the first metal prefabricated layer formed by the magnetic filtration multi-arc ion plating method is higher by one order of magnitude than that formed by magnetron sputtering and other methods, and further, the first metal prefabricated layer formed by the magnetic filtration multi-arc ion plating method has higher bonding force with the metal substrate and higher reliability.

Preferably, the working atmosphere of the magnetic filtration multi-arc ion plating method is argon, and Ar is generated after argon ionization⁺The target material is impacted under the action of the electric field. The flow rate of the argon gas is 20sccm to 50sccm, and the vacuum degree is 2.0 multiplied by 10^-2Pa～6.0×10^-2Pa. Ar in the chamber⁺The more kinetic energy is generated, the more favorable the target ions escape.

Preferably, the arc current of the magnetic filtration multi-arc ion plating method is 45A-60A, the extraction current is 7A-11A, the bias voltage applied to the metal substrate is 5V-10V, and the deposition time is 35 seconds-65 seconds. Furthermore, the thickness of the first metal prefabricated layer obtained by deposition is 35 nm-65 nm.

Similarly, in step S3, a second metal prefabricated layer is deposited on the first metal prefabricated layer by using a magnetic filtering multi-arc ion plating method. And the magnetic filtration multi-arc ion plating method belongs to ion plating, when a second metal prefabricated layer is formed through deposition, an alloy prefabricated layer of a first metal and a second metal is easily formed between the first metal prefabricated layer and the second metal prefabricated layer, so that the binding force of the first metal prefabricated layer and the second metal prefabricated layer is improved.

Preferably, the arc current of the magnetic filtration multi-arc ion plating method is 45A to 60A, the extraction current is 7A to 11A, the bias voltage applied to the metal substrate is 5V to 10V, and the deposition time is 60 seconds to 100 seconds. Thus, a bias applied to the metal substrate generates an electric field under which the charged second metal ions have a certain energy, such as Ti⁴⁺Under the action of an electric field of 5V, the energy of the ion source is 20eV, and the formation of the alloy prefabricated layer of the first metal and the second metal and the thickness of the alloy prefabricated layer are controlled by controlling the energy of the ion.

Further, the thickness of the second metal prefabricated layer obtained by deposition is 50 nm-85 nm, the thickness of the formed alloy prefabricated layer is 10 nm-15 nm, and at the moment, the thickness of the first metal prefabricated layer is reduced to 25 nm-50 nm.

The second metal prefabricated layer can comprise a titanium prefabricated layer, an aluminum prefabricated layer, a zirconium prefabricated layer and the like, and the energy storage density can reach 15J/cm although the dielectric constant is only about 120 in consideration of the fact that the titanium dioxide ceramic film has high breakdown field intensity (more than 1000kV/cm)³The energy storage density of the energy storage ceramic film can be further improved by adopting the titanium dioxide ceramic film. Therefore, the second metal preform layer is preferably a titanium preform layer.

In step S4, a hall ion source is preferably used to oxidize the second metal layer, the flow rate of oxygen is 50sccm to 80sccm, and the vacuum degree is 5.0 × 10^-2Pa～8.0×10^-2Pa, the voltage of the Hall ion source is 1000V-2000V, the current is 0.6A-2A, and the time of the oxidation treatment is 10 minutes-20 minutes. The second metal prefabricated layer is subjected to surface oxidation treatment through high-energy oxygen Hall ions, so that the surface layer of the second metal prefabricated layer can be oxidized to form the second metal oxidation prefabricated layer. The second metal oxide prefabricated layer belongs to the prefabricated layer grown in situ, so that the second metal oxide prefabricated layer has strong binding force with the second metal prefabricated layer and high reliability.

Further, the thickness of the second metal oxide prefabricated layer obtained after the oxidation treatment is 10 nm-15 nm, and at the moment, the thickness of the second metal oxide prefabricated layer is reduced to 40 nm-70 nm.

Since the thickness of the second metal oxide pre-formed layer obtained by the oxidation treatment is limited, a second metal oxide pre-formed film is deposited again on the second metal oxide pre-formed layer through the step S5, the thickness of the second metal oxide pre-formed film is 40nm to 3.2 μm, the grain size of the second metal oxide pre-formed film is 20nm to 200nm, and the film structure is dense. The components of the second metal oxide prefabricated layer and the second metal oxide prefabricated film are the same, so that the second metal oxide prefabricated layer and the second metal oxide prefabricated film have strong binding force, and form a prefabricated ceramic film, and further obtain the prefabricated energy storage ceramic film which comprises a metal substrate, and a first metal prefabricated layer, an alloy prefabricated layer, a second metal oxide prefabricated layer and a second metal oxide prefabricated film which are sequentially formed on the metal substrate.

In step S5, the second metal oxide pre-formed film may be formed by a magnetron sputtering method, a magnetic filtration multi-arc ion plating method, or the like. When the magnetron sputtering method is adopted, the working atmosphere of the magnetron sputtering method is argon, the introducing flow of the argon is 30 sccm-120 sccm, and the vacuum degree is 0.1 Pa-0.5 Pa. In the magnetron sputtering method, the magnetron sputtering power is 100W-200W, and the deposition time is 0.5 min-40 min.

Considering that the second metal prefabricated layer is preferably a titanium prefabricated layer, the second metal oxide prefabricated layer is a titanium dioxide prefabricated layer, and the second metal oxide prefabricated film is a titanium dioxide prefabricated film.

In step S6, the prefabricated energy storage ceramic film is subjected to heat treatment, wherein the temperature of the heat treatment is 300-500 ℃, and the time is 30-300 minutes. The heat treatment is carried out at the temperature of 300-500 ℃ for 30-300 minutes, so that a large amount of lattice mismatch, lattice reconstruction, impurities, phase change and other non-equilibrium defects in the first metal prefabricated layer, the alloy prefabricated layer, the second metal oxide prefabricated layer and the second metal oxide prefabricated film can be eliminated, the internal stress is obviously reduced, and the energy storage ceramic film is obtained.

Preferably, argon is introduced during the heat treatment to prevent oxidation. The flow rate of the argon is 100 sccm-200 sccm, and the vacuum degree is 0.1 Pa-1 Pa.

The energy storage ceramic film prepared by the preparation method has strong bonding force because: the first metal layer and the first metal layer are made of the same material as the metal substrate, and the bonding force between the two layers is strong according to the similar compatible principle; secondly, depositing a first metal layer and a second metal layer on the metal substrate by a magnetic filtration multi-arc ion plating method, wherein the deposited particles have high energy and strong binding force; thirdly, an alloy layer of the first metal and the second metal can be formed between the first metal layer and the second metal layer by a magnetic filtration multi-arc ion plating method, so that the bonding force of the first metal layer and the second metal layer is improved; the fourth metal oxide layer is obtained by in-situ growth of the second metal layer and has strong bonding force with the second metal layer; fifthly, according to the similar compatible principle, the bonding force of the second metal oxide film and the second metal oxide layer is strong.

The preparation method can be carried out in the same chamber, has high preparation efficiency, good microstructures such as crystallinity and grain size of the ceramic film and low internal stress, and improves the energy storage performance of the energy storage ceramic film.

As shown in fig. 1, the present invention further provides an energy storage ceramic thin film, which includes a metal substrate 10, and a first metal layer 20, an alloy layer 30, a second metal layer 40, a second metal oxide layer 41 and a second metal oxide thin film 42 sequentially formed on the metal substrate 10; the material of the first metal layer 20 is the same as that of the metal substrate 10, and the alloy layer 30 is an alloy layer formed by a first metal and a second metal. The second metal oxide layer 41 and the second metal oxide thin film 42 constitute a ceramic thin film 50.

Preferably, the energy storage ceramic film is prepared by the preparation method. The first metal layer 20, the alloy layer 30, the second metal layer 40, the second metal oxide layer 41 and the second metal oxide film 42 are obtained by performing heat treatment on the first metal prefabricated layer, the alloy prefabricated layer, the second metal oxide prefabricated layer and the second metal oxide prefabricated film, and have better crystal lattices and lower nonequilibrium defects and internal stress.

Preferably, the surface roughness of the metal substrate 10 is 10nm to 0.4 μm.

Preferably, the thickness of the metal substrate 10 is 6 μm to 18 μm; and/or

The surface tension of the metal substrate 10 is not less than 60 dynes; and/or

The thickness of the first metal layer 20 is 20nm to 40 nm; and/or

The thickness of the second metal layer 40 is 30 nm-60 nm; and/or

The thickness of the alloy layer 30 is 5nm to 10 nm; and/or

The thickness of the second metal oxide layer 41 is 5nm to 10 nm; and/or

The thickness of the second metal oxide thin film 42 is 25nm to 1.99 μm, and the grain size of the second metal oxide thin film 42 is 30nm to 300 nm.

Preferably, the metal substrate 10 includes a copper foil, the first metal layer 20 includes a copper layer, the alloy layer 30 includes a copper-titanium alloy layer, the second metal layer 40 includes a titanium layer, the second metal oxide layer 41 includes a titanium dioxide layer, and the second metal oxide film 42 includes a titanium dioxide film.

In the energy storage ceramic film, the first metal layer and the metal substrate are firmly combined according to the similar compatible principle, the first metal layer and the second metal layer improve the binding force through the alloy layer formed by the first metal and the second metal, the second metal oxide layer is the oxide of the second metal layer, the binding force between the two layers is strong, and the second metal oxide film and the second metal oxide layer are the same material layer and have strong binding force. Therefore, the energy storage ceramic film can reduce the surface roughness of the metal substrate and ensure the binding force, thereby simultaneously improving the energy storage performance and the reliability of the energy storage ceramic film.

Hereinafter, the film capacitor will be further described by the following specific examples.

Example 1:

using flexible low-roughness copper foil as substrate, thickness is 6 μm, surface roughness is 10nm, placing in vacuum chamber, and vacuumizing to 3 × 10^-3Pa. Heating the vacuum chamber to 150 deg.C, maintaining for 10min, introducing argon gas at flow rate of 20sccm and vacuum degree of the vacuum chamber of 2 × 10^-2And Pa, opening the Hall ion source, setting the voltage of the Hall ion source to be 1000V and the current to be 0.5A, and treating for 1min to enable the surface tension of the copper foil to reach 60 dynes.

The vacuum degree is maintained at 2.0X 10^-2Pa, argon gas flow is 20sccm, metal copper is used as a target material, a first magnetic filtration multi-arc ion plating power supply is turned on, arc current is adjusted to 50A, current 9A is led out, bias voltage applied to the copper foil is 5V, deposition time is 35s, a copper prefabricated layer with the thickness of 35nm is formed on the copper foil, and the first magnetic filtration multi-arc ion plating power supply is turned off. Taking metal titanium as a target material, turning on a second magnetic filtration multi-arc ion plating power supply, and adjusting arc electricityAnd when the voltage is 50A, the current is extracted by 10A, the bias voltage applied to the copper foil is 7V, the deposition time is 60s, and a titanium prefabricated layer with the thickness of 50nm and a copper-titanium alloy prefabricated layer with the thickness of 10nm are obtained, wherein the thickness of the copper prefabricated layer is reduced to 25 nm.

Closing the second magnetic filtration multi-arc ion plating power supply and the argon switch valve, opening the oxygen valve, adjusting the oxygen flow to 50sccm and the vacuum degree to 5.0 × 10^-2And Pa, opening a Hall ion source, wherein the voltage is 1000V, the current is 0.6A, and the treatment time is 10min, so that the surface of the titanium prefabricated layer is oxidized to obtain a titanium dioxide prefabricated layer with the thickness of 10nm, and the thickness of the titanium prefabricated layer is reduced to 40 nm.

Closing the Hall ion source and the oxygen valve, opening the argon valve, adjusting the argon flow to be 30sccm, the vacuum degree to be 0.1Pa, opening the magnetron sputtering power supply, adjusting the power to be 100W, and the deposition time to be 30s to obtain a titanium dioxide prefabricated film with the thickness of 40nm, wherein the grain size of the titanium dioxide prefabricated film is 20nm, and further obtaining the prefabricated energy storage ceramic film.

And closing the magnetron sputtering power supply and the argon valve, opening the flow of large argon to 100sccm, enabling the vacuum degree of the vacuum chamber to be 0.1Pa, heating the vacuum chamber to 300 ℃, keeping the temperature for 30min, and eliminating the residual stress of the prefabricated energy storage ceramic film to obtain the energy storage ceramic film. The energy storage ceramic film comprises a copper foil, and a copper layer, a copper-titanium alloy layer, a titanium dioxide layer and a titanium dioxide film which are sequentially formed on the copper foil, wherein the titanium dioxide layer and the titanium dioxide film form the ceramic film.

And depositing copper metal on the titanium dioxide film of the energy storage film by a magnetron sputtering process to be used as an upper electrode, and carrying out electrical property test.

Tests prove that the thickness of a titanium dioxide film in the energy storage ceramic film is 25nm, the grain size of the titanium dioxide film is 30nm, the thickness of a titanium dioxide layer is 5nm, the thickness of a titanium layer is 30nm, the thickness of a copper-titanium alloy layer is 5nm, the thickness of a copper layer is 20nm, and the bonding force between the layers is 5B. The energy storage ceramic film has flexibility, the minimum bending radius is 2mm, the breakdown field strength is 2000kV/cm, and the energy storage density is 35J/cm³. After 1000 bends, between layersThe binding force is 5B, and the energy storage density is 34.8J/cm³The retention rate is 99.5%, and the film capacitor can be applied to film capacitors.

Example 2:

using flexible low-roughness copper foil as substrate, thickness of 10 μm and surface roughness of 20nm, placing in vacuum chamber, and vacuumizing to 3 × 10^-3Pa. Heating the vacuum chamber to 100 deg.C, maintaining for 20min, introducing argon gas with flow rate of 30sccm and vacuum degree of 3 × 10^-2And Pa, opening the Hall ion source, setting the voltage of the Hall ion source to be 800V and the current to be 0.6A, and treating for 5min to enable the surface tension of the copper foil to reach 65 dynes.

The vacuum degree is maintained at 3.0X 10^-2Pa, argon gas flow is 30sccm, metal copper is used as a target material, a first magnetic filtration multi-arc ion plating power supply is turned on, arc current is adjusted to 55A, current 10A is led out, bias voltage applied to the copper foil is 6V, deposition time is 45s, a copper prefabricated layer with the thickness of 45nm is formed on the copper foil, and the first magnetic filtration multi-arc ion plating power supply is turned off. And (3) taking metal titanium as a target material, turning on a second magnetic filtration multi-arc ion plating power supply, adjusting the arc current to 45A, leading out current 10A, applying a bias voltage of 8V to the copper foil, and depositing for 70s to obtain a titanium prefabricated layer with the thickness of 60nm and a copper-titanium alloy prefabricated layer with the thickness of 11nm, wherein the thickness of the copper prefabricated layer is reduced to 34 nm.

Closing the second magnetic filtration multi-arc ion plating power supply and the argon switch valve, opening the oxygen valve, adjusting the oxygen flow to 60sccm and the vacuum degree to 6.0 × 10^-2And Pa, opening the Hall ion source, wherein the voltage is 1200V, the current is 0.7A, and the treatment time is 15min, so that the surface of the titanium prefabricated layer is oxidized to obtain a titanium dioxide prefabricated layer with the thickness of 12nm, and the thickness of the titanium prefabricated layer is reduced to 48 nm.

Closing the Hall ion source and the oxygen valve, opening the argon valve, adjusting the argon flow to be 60sccm, adjusting the vacuum degree to be 0.4Pa, opening the magnetron sputtering power supply, adjusting the power to be 120W, and depositing for 1min to obtain a titanium dioxide prefabricated film with the thickness of 80nm, wherein the grain size of the titanium dioxide prefabricated film is 80nm, and further obtaining the prefabricated energy storage ceramic film.

And closing the magnetron sputtering power supply and the argon valve, opening the flow of large argon to 150sccm, enabling the vacuum degree of the vacuum chamber to be 0.5Pa, heating the vacuum chamber to 400 ℃, keeping the temperature for 3h, and eliminating the residual stress of the prefabricated energy storage ceramic film to obtain the energy storage ceramic film. The energy storage ceramic film comprises a copper foil, and a copper layer, a copper-titanium alloy layer, a titanium dioxide layer and a titanium dioxide film which are sequentially formed on the copper foil, wherein the titanium dioxide layer and the titanium dioxide film form the ceramic film.

And depositing silver metal on the titanium dioxide film of the energy storage film through a magnetron sputtering process to be used as an upper electrode, and carrying out electrical property test.

Tests prove that the thickness of a titanium dioxide film in the energy storage ceramic film is 50nm, the grain size of the titanium dioxide film is 120nm, the thickness of a titanium dioxide layer is 7nm, the thickness of a titanium layer is 40nm, the thickness of a copper-titanium alloy layer is 6nm, the thickness of a copper layer is 29nm, and the bonding force between the layers is 5B. The energy storage ceramic film has flexibility, the minimum bending radius is 5mm, the breakdown field strength is 4000kV/cm, and the energy storage density is 65J/cm³. After 1000 times of bending, the binding force between layers is 5B, and the energy storage density is 64.7J/cm³The retention rate is 99.6%, and the film capacitor can be applied to film capacitors.

Example 3:

using flexible low-roughness copper foil as substrate, thickness of 12 μm and surface roughness of 80nm, placing in vacuum chamber, and vacuumizing to 3 × 10^-3Pa. Heating the vacuum chamber to 300 deg.C, holding for 30min, introducing argon gas with flow rate of 50sccm and vacuum degree of 6 × 10^-2And Pa, opening the Hall ion source, setting the voltage of the Hall ion source to be 1500V and the current to be 2A, and treating for 10min to enable the surface tension of the copper foil to reach 75 dynes.

The vacuum degree is kept at 6.0X 10^-2Pa, the argon flow is 50sccm, the metal copper is used as a target material, a first magnetic filtration multi-arc ion plating power supply is turned on, the arc current is adjusted to 60A, the current is led out to be 11A, the bias voltage applied to the copper foil is 10V, the deposition time is 65s, a copper prefabricated layer with the thickness of 65nm is formed on the copper foil, and the first magnetic filtration multi-arc ion plating power supply is turned off. Using metallic titanium asAnd (3) turning on a second magnetic filtration multi-arc ion plating power supply, adjusting the arc current to 60A, leading out current 11A, applying bias voltage to the copper foil to 10V, and depositing for 100s to obtain a titanium prefabricated layer with the thickness of 85nm and a copper-titanium alloy prefabricated layer with the thickness of 15nm, wherein the thickness of the copper prefabricated layer is reduced to 50 nm.

Closing the second magnetic filtration multi-arc ion plating power supply and the argon switch valve, opening the oxygen valve, adjusting the oxygen flow to 80sccm and the vacuum degree to 8.0 × 10^-2And Pa, opening the Hall ion source, wherein the voltage is 2000V, the current is 2A, and the treatment time is 20min, so that the surface of the titanium prefabricated layer is oxidized to obtain a titanium dioxide prefabricated layer with the thickness of 15nm, and the thickness of the titanium prefabricated layer is reduced to 70 nm.

Closing the Hall ion source and the oxygen valve, opening the argon valve, adjusting the argon flow to 120sccm, the vacuum degree to 0.5Pa, opening the magnetron sputtering power supply, adjusting the power to 200W, and the deposition time to 40min to obtain a titanium dioxide prefabricated film with the thickness of 3.2 mu m, wherein the grain size of the titanium dioxide prefabricated film is 200nm, thereby obtaining the prefabricated energy storage ceramic film.

And closing the magnetron sputtering power supply and the argon valve, opening the flow of large argon to 200sccm, enabling the vacuum degree of the vacuum chamber to be 1Pa, heating the vacuum chamber to 500 ℃, keeping the temperature for 5h, and eliminating the residual stress of the prefabricated energy storage ceramic film to obtain the energy storage ceramic film. The energy storage ceramic film comprises a copper foil, and a copper layer, a copper-titanium alloy layer, a titanium dioxide layer and a titanium dioxide film which are sequentially formed on the copper foil, wherein the titanium dioxide layer and the titanium dioxide film form the ceramic film.

And depositing platinum metal on the titanium dioxide film of the energy storage film through a magnetron sputtering process to be used as an upper electrode, and carrying out electrical property test.

Tests prove that the thickness of the titanium dioxide film in the energy storage ceramic film is 1.99 mu m, the grain size of the titanium dioxide film is 300nm, the thickness of the titanium dioxide layer is 10nm, the thickness of the titanium layer is 60nm, the thickness of the copper-titanium alloy layer is 10nm, the thickness of the copper layer is 40nm, and the bonding force between the layers is 5B. The energy storage ceramic film has flexibility, the minimum bending radius is 20mm, the breakdown field strength is 2000kV/cm,the energy storage density is 25J/cm³. After 1000 times of bending, the binding force between layers is 5B, and the energy storage density is 24.9J/cm³The retention rate is 99.8%, and the film capacitor can be applied to film capacitors.

Example 4:

using flexible low-roughness copper foil as substrate, its thickness is 18 micrometers and surface roughness is 400nm, placing it in vacuum chamber, vacuumizing to 3X 10^-3Pa. Heating the vacuum chamber to 300 deg.C, maintaining for 30min, introducing argon gas with flow rate of 40sccm and vacuum degree of 4 × 10^-2And Pa, opening the Hall ion source, setting the voltage of the Hall ion source to be 800V and the current to be 0.5A, and treating for 7min to enable the surface tension of the copper foil to reach 65 dynes.

The vacuum degree is maintained at 3.0X 10^-2Pa, the argon flow is 40sccm, the metal copper is used as a target material, a first magnetic filtration multi-arc ion plating power supply is turned on, the arc current is adjusted to 45A, the current is led out to be 7A, the bias voltage applied to the copper foil is 6V, the deposition time is 50s, a copper prefabricated layer with the thickness of 50nm is formed on the copper foil, and the first magnetic filtration multi-arc ion plating power supply is turned off. And (3) taking metal titanium as a target material, turning on a second magnetic filtration multi-arc ion plating power supply, adjusting the arc current to 45A, leading out a current of 7A, applying a bias voltage of 5V to the copper foil, and depositing for 100s to obtain a titanium prefabricated layer with the thickness of 60nm and a copper-titanium alloy prefabricated layer with the thickness of 10nm, wherein the thickness of the copper prefabricated layer is reduced to 40 nm.

Closing the second magnetic filtration multi-arc ion plating power supply and the argon switch valve, opening the oxygen valve, adjusting the oxygen flow to 60sccm and the vacuum degree to 6.0 × 10^-2And Pa, opening a Hall ion source, wherein the voltage is 1500V, the current is 1.2A, and the treatment time is 10min, so that the surface of the titanium prefabricated layer is oxidized to obtain a titanium dioxide prefabricated layer with the thickness of 13nm, and the thickness of the titanium prefabricated layer is reduced to 47 nm.

Closing the Hall ion source and the oxygen valve, opening the argon valve, adjusting the argon flow to be 100sccm, the vacuum degree to be 0.3Pa, opening the magnetron sputtering power supply, adjusting the power to be 150W, and depositing for 30min to obtain a titanium dioxide prefabricated film with the thickness of 2.4 mu m, wherein the grain size of the titanium dioxide prefabricated film is 150nm, thereby obtaining the prefabricated energy storage ceramic film.

And closing the magnetron sputtering power supply and the argon valve, opening the flow of large argon to 150sccm, enabling the vacuum degree of the vacuum chamber to be 0.5Pa, heating the vacuum chamber to 450 ℃, keeping the temperature for 4h, and eliminating the residual stress of the prefabricated energy storage ceramic film to obtain the energy storage ceramic film. The energy storage ceramic film comprises a copper foil, and a copper layer, a copper-titanium alloy layer, a titanium dioxide layer and a titanium dioxide film which are sequentially formed on the copper foil, wherein the titanium dioxide layer and the titanium dioxide film form the ceramic film.

Tests prove that the thickness of a titanium dioxide film in the energy storage ceramic film is 1.49 mu m, the grain size of the titanium dioxide film is 200nm, the thickness of a titanium dioxide layer is 8nm, the thickness of a titanium layer is 42nm, the thickness of a copper-titanium alloy layer is 5nm, the thickness of a copper layer is 30nm, and the bonding force between the layers is 5B. The energy storage ceramic film has flexibility, the minimum bending radius is 12mm, the breakdown field strength is 2500kV/cm, and the energy storage density is 30J/cm³. After 1000 times of bending, the binding force between layers is 5B, and the energy storage density is 29.8J/cm³The retention rate is 99.5%, and the film capacitor can be applied to film capacitors.

Example 5:

using flexible low-roughness copper foil as substrate, thickness of 13 μm and surface roughness of 250nm, placing in vacuum chamber, and vacuumizing to 3 × 10^-3Pa. Heating the vacuum chamber to 200 deg.C, maintaining for 25min, introducing argon gas with flow rate of 40sccm and vacuum degree of 5 × 10^-2And Pa, opening the Hall ion source, setting the voltage of the Hall ion source to be 1200V and the current to be 1.2A, and treating for 6min to enable the surface tension of the copper foil to reach 65 dynes.

The vacuum degree is maintained at 2.5X 10^-2Pa, argon gas flow of 25sccm, metal copper as target material, turning on the first magnetic filtration multi-arc ion plating power supply, adjusting arc current to 50A, leading out current 9A, applying bias voltage to copper foil of 8V, depositing for 40s, and forming on the copper foil with thickness of 40nAnd (5) closing the first magnetic filtration multi-arc ion plating power supply for the copper prefabricated layer of m. And (3) taking metal titanium as a target material, turning on a second magnetic filtration multi-arc ion plating power supply, adjusting the arc current to 55A, leading out a current of 11A, applying a bias voltage of 10V to the copper foil, and depositing for 80s to obtain a titanium prefabricated layer with the thickness of 65nm and a copper-titanium alloy prefabricated layer with the thickness of 15nm, wherein the thickness of the copper prefabricated layer is reduced to 25 nm.

Closing the second magnetic filtration multi-arc ion plating power supply and the argon switch valve, opening the oxygen valve, adjusting the oxygen flow to 70sccm and the vacuum degree to 7.0 × 10^-2And Pa, opening a Hall ion source, wherein the voltage is 1500V, the current is 1.5A, and the treatment time is 15min, so that the surface of the titanium prefabricated layer is oxidized to obtain a titanium dioxide prefabricated layer with the thickness of 13nm, and the thickness of the titanium prefabricated layer is reduced to 52 nm.

Closing the Hall ion source and the oxygen valve, opening the argon valve, adjusting the argon flow to be 110sccm, the vacuum degree to be 0.4Pa, opening the magnetron sputtering power supply, adjusting the power to be 170W, and depositing for 20min to obtain a titanium dioxide prefabricated film with the thickness of 1.6 mu m, wherein the grain size of the titanium dioxide prefabricated film is 50nm, thereby obtaining the prefabricated energy storage ceramic film.

And closing the magnetron sputtering power supply and the argon valve, opening the flow of large argon to 180sccm, enabling the vacuum degree of the vacuum chamber to be 0.8Pa, heating the vacuum chamber to 350 ℃, keeping the temperature for 4h, and eliminating the residual stress of the prefabricated energy storage ceramic film to obtain the energy storage ceramic film. The energy storage ceramic film comprises a copper foil, and a copper layer, a copper-titanium alloy layer, a titanium dioxide layer and a titanium dioxide film which are sequentially formed on the copper foil, wherein the titanium dioxide layer and the titanium dioxide film form the ceramic film.

Tests prove that the thickness of the titanium dioxide film in the energy storage ceramic film is 1.2 mu m, the grain size of the titanium dioxide film is 100nm, the thickness of the titanium dioxide layer is 8nm, the thickness of the titanium layer is 46nm, the thickness of the copper-titanium alloy layer is 10nm, the thickness of the copper layer is 20nm, and the bonding force between the layers is 5B. The stored energyThe ceramic film has flexibility, the minimum bending radius is 8mm, the breakdown field strength is 3000kV/cm, and the energy storage density is 40J/cm³. After 1000 times of bending, the binding force between layers is 5B, and the energy storage density is 39.8J/cm³The retention rate is 99.5%, and the film capacitor can be applied to film capacitors.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present invention, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the inventive concept, which falls within the scope of the present invention. Therefore, the protection scope of the present patent shall be subject to the appended claims.

Claims

1. A film capacitor is characterized by comprising a dielectric film and an electrode layer, wherein the dielectric film comprises a metal substrate, a first metal layer, a second metal oxide layer and a second metal oxide film which are sequentially formed on the metal substrate, and the electrode layer is formed on the second metal oxide film;

2. The thin film capacitor of claim 1, wherein the first metal layer and the second metal layer are deposited by a magnetic filtering multi-arc ion plating method, and wherein the first metal in the first metal layer and the second metal in the second metal layer form the alloy layer when the second metal layer is deposited by the magnetic filtering multi-arc ion plating method.

3. The thin film capacitor of claim 1, wherein the surface roughness of the metal substrate is 10nm to 400 nm.

4. A thin film capacitor in accordance with claim 1, wherein the thickness of the metal substrate is 6 μm to 18 μm; and/or

The surface tension of the metal substrate is more than or equal to 60 dyne.

5. A thin film capacitor according to claim 1, wherein the thickness of the first metal layer is 20nm to 40 nm.

6. A thin film capacitor according to claim 1, wherein the thickness of the second metal layer is 30nm to 60 nm.

7. The film capacitor of claim 1, wherein the alloy layer has a thickness of 5nm to 10 nm.

8. A thin film capacitor in accordance with claim 1, wherein the thickness of the second metal oxide layer is 5nm to 10 nm.

9. A thin film capacitor in accordance with claim 1, wherein the thickness of the second metal oxide thin film is 25nm to 1.99 μm, and the crystal grain size of the second metal oxide thin film is 30nm to 300 nm.

10. The film capacitor of claim 1, wherein the metal substrate comprises a copper foil, the first metal layer comprises a copper layer, the alloy layer comprises a copper titanium alloy layer, the second metal layer comprises a titanium layer, the second metal oxide layer comprises a titanium dioxide layer, and the second metal oxide film comprises a titanium dioxide film.