阅读说明：本技术 一种低介电常数高熵薄膜及其制备方法 (Low-dielectric-constant high-entropy film and preparation method thereof ) 是由 娄晓杰 乔文婧 于 2021-07-26 设计创作，主要内容包括：本发明涉及薄膜材料领域,具体涉及一种低介电常数高熵薄膜及其制备方法,本发明低介电常数高熵薄膜包括：SrTiO-(3)基片、置于SrTiO-(3)基片表面的La-(0.7)Sr-(0.3)MnO-(3)缓冲层以及设置于La-(0.7)Sr-(0.3)MnO-(3)缓冲层表面的Ba(Zr-(0.2)Sn-(0.2)Ti-(0.2)Hf-(0.2)Me-(0.2))O-(3)薄膜,Me为过渡族金属元素离子。本发明低介电常数高熵薄膜具有比较致密的结构,并具有低介电常数和低介电损耗的特征。(The invention relates to the field of thin film materials, in particular to a low dielectric constant high-entropy thin film and a preparation method thereof, wherein the low dielectric constant high-entropy thin film comprises the following components: SrTiO 3 Substrate, disposed on SrTiO 3 La of substrate surface 0.7 Sr 0.3 MnO 3 Buffer layer and arranged on La 0.7 Sr 0.3 MnO 3 Ba (Zr) on surface of buffer layer 0.2 Sn 0.2 Ti 0.2 Hf 0.2 Me 0.2 )O 3 And Me is transition metal element ions. The low-dielectric-constant high-entropy film has a compact structure and has the characteristics of low dielectric constant and low dielectric loss.)

1. A low dielectric constant high entropy film, comprising: SrTiO₃Substrate, disposed on SrTiO₃La of substrate surface_0.7Sr_0.3MnO₃Buffer layer and arranged on La_0.7Sr_0.3MnO₃Ba (Zr) on surface of buffer layer_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃And Me is transition metal element ions.

2. A low-dielectric-constant high-entropy film according to claim 1, wherein La_0.7Sr_0.3MnO₃The thickness range of the buffer layer is 50-60 nm, Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The thickness of the film is 100 to 400 nm.

3. A low-dielectric-constant high-entropy film according to claim 1, wherein Me is Y, Nb, Ta, V, Mo or W.

4. A low-dielectric-constant high-entropy film as claimed in claim 1, wherein SrTiO₃Single crystal SrTiO with substrate grown in (001) orientation₃A substrate.

5. A preparation method of a low-dielectric-constant high-entropy film is characterized by comprising the following steps:

in SrTiO₃Preparation of La on the surface of a substrate_0.7Sr_0.3MnO₃A buffer layer with Ba (Zr) prepared on the surface_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃And (3) forming the film to obtain the low-dielectric-constant high-entropy film, wherein Me is transition metal element ions.

6. The method for preparing a low-dielectric-constant high-entropy film according to claim 5, wherein La is_0.7Sr_0.3MnO₃Buffer layer and Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The films are all prepared by a magnetron sputtering method, Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃And annealing the thin film to obtain the low-dielectric-constant high-entropy thin film.

7. A low dielectric constant according to claim 5The preparation method of the constant high-entropy film is characterized in that the film is prepared by magnetron sputtering Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃BaCO is adopted as ceramic target material in film forming₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂The powder and Me oxide powder are prepared by ball milling, presintering, granulating, molding and sintering, wherein the sintering temperature is lower than the system phase forming temperature by 100-200 ℃;

magnetron sputtering of Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Film and La_0.7Sr_0.3MnO₃In the process of buffering the layer: la_0.7Sr_0.3MnO₃Ceramic target material of buffer layer and Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃After the ceramic target material of the film is installed, pre-sputtering for 1-2 hours in a mixed gas atmosphere of argon and oxygen in a volume ratio of (3.9-4.1): 1 to remove impurities on the surface of the target material; then the deposition cavity of the magnetron sputtering system is vacuumized, and the vacuum degree is not less than 10^-5Pa; introducing the mixed gas of argon and oxygen into the deposition chamber to ensure that the air pressure in the deposition chamber is 1.0-1.2 Pa; then SrTiO is added₃Baking the substrate at 600-650 deg.C under 1.0-1.2 Pa for 10-15 min to remove SrTiO₃A substrate surface attachment; then slowly introducing the mixed gas of argon and oxygen into the deposition cavity and adjusting the air pressure to be 1.0-1.2 Pa; then SrTiO₃Growing La on a substrate_0.7Sr_0.3MnO₃Buffer layer, then on La_0.7Sr_0.3MnO₃Growing Ba (Zr) on the buffer layer_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A film; ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃After the growth of the film is finished, annealing for 10-15 min under the air pressure of 1.0-1.2 Pa; and after the annealing is finished, taking out the sample when the temperature is reduced to the room temperature to obtain the low-dielectric-constant high-entropy film.

8. The method for preparing a low-dielectric-constant high-entropy film according to claim 5, wherein La is_0.7Sr_0.3MnO₃The thickness range of the buffer layer is 50-60 nm, Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The thickness of the film is 100 to 400 nm.

9. A method for preparing a low dielectric constant high entropy film as claimed in claim 5, wherein Me is Y, Nb, T, V, Mo or W.

10. A method for preparing a low dielectric constant high entropy film as claimed in claim 5, wherein SrTiO₃Single crystal SrTiO with substrate grown in (001) orientation₃A substrate.

Technical Field

The invention relates to the field of manufacturing of super-large-scale integrated circuits, in short, to a low-dielectric-constant high-entropy film and a preparation method thereof.

Background

In microelectronic circuits, in order to achieve high speed, low dynamic power consumption, and low crosstalk noise of very large scale integrated device chip interconnections, materials with low dielectric constants are required as interlayer dielectrics. For integrated circuits, the smaller the dielectric constant of the interlevel dielectric, the higher the interconnectivity of the circuit, and the smaller the switching delay. Meanwhile, the threshold voltage displacement caused by the moving charges is small, and the leakage current is small, so that the power consumption of the integrated circuit is reduced. In general, scientists have used compounds with very low polarizability and introduced pores to reduce the dielectric constant. However, such porous materials often have difficulty meeting the stringent requirements of low dielectric constant mechanical properties for microelectronic circuits. Most electronic systems (e.g., computers, chips, etc.) are comprised of Integrated Circuits (ICs) and conductive paths that provide power to and transmit data to the ICs. The more advanced integrated circuits, the more stringent certain characteristics of dielectric or insulating materials are required. Furthermore, it is critical that the interlayer dielectric retain its specific electrical, physical and chemical properties during the embedding of the device and subsequent processing. The conventional choice cannot be relied upon again due to its limited temperature range and accelerated shrinking of feature sizes below 0.25 μm. Therefore, new low dielectric constant and low dielectric loss materials must be sought for replacement.

At present, SiO having excellent thermal stability₂It has been the insulating material used between metal interconnection wires, and aluminum metal is the main material of interconnection wires. However, as the integration degree of the integrated circuit is higher, the wires in the chip are denser and the space and the width are smaller, so that the parasitic resistance-capacitance effect between the resistor (R) and the capacitor (C) is more obvious. When the device size is less than 0.25 microns, the resistance-capacitance delay (RC delay) causes power dissipation, device heating, line-to-line interference, and signal delay. Therefore, in addition to replacing aluminum wires with copper wires (with a resistivity of only 60% of aluminum), materials with lower dielectric constants (k) were developed to replace SiO₂(k-4) to reduce the RC delay has become an important issue in the current semiconductor integrated circuit field.

Generally, there are two ways to reduce the dielectric constant of a material. One is to reduce the number of polarized molecules per unit volume by reducing the density of the material, which is mainly achieved by introducing pores into the material. When pores having a nano size are introduced into a material, the dielectric constant of the material is rapidly decreased. However, as the pores in the material increase, the mechanical property and the corrosion resistance of the material are poor, and the pore-forming agent in the material cannot be completely removed easily. Another approach is to lower the dielectric constant by reducing the polarization of the material. The method generally selects materials with low polarization capability, such as some organic polymer materials, although the dielectric constant is low, most of the mechanical properties are not stable, and the stability of the integrated circuit in a high-temperature environment cannot be guaranteed.

The existing low-k material is mainly SiO₂(k-4) and derivatives thereof (k-2.8-3.7), such as: amorphous plasma enhanced chemical vapor deposited carbon doped silica, organic polymers, organosilicates, and the like. Among them, the dielectric constant of a low dielectric constant high entropy thin film prepared by a chemical vapor deposition (MOCVD) method is generally difficult to be very low, and organic polymers are difficult to be integrated into the existing integrated circuit process due to poor thermal stability.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provides a low-dielectric-constant high-entropy film and a preparation method thereof.

The technical scheme adopted by the invention is as follows:

a low dielectric constant high entropy film comprising: SrTiO₃Substrate, disposed on SrTiO₃La of substrate surface_0.7Sr_0.3MnO₃Buffer layer and arranged on La_0.7Sr_0.3MnO₃Ba (Zr) on surface of buffer layer_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃And Me is transition metal element ions.

Preferably, La_0.7Sr_0.3MnO₃The thickness range of the buffer layer is 50-60 nm, Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The thickness of the film is 100 to 400 nm.

Preferably, Me is Y, Nb, Ta, V, Mo or W.

Preferably, SrTiO₃Single crystal SrTiO with substrate grown in (001) orientation₃A substrate.

The invention also provides a preparation method of the low-dielectric-constant high-entropy film, which comprises the following steps:

in SrTiO₃Preparation of La on the surface of a substrate_0.7Sr_0.3MnO₃A buffer layer with Ba (Zr) prepared on the surface_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃And (3) forming the film to obtain the low-dielectric-constant high-entropy film, wherein Me is transition metal element ions.

Preferably, La_0.7Sr_0.3MnO₃Buffer layer and Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The films are all prepared by a magnetron sputtering method, Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃And annealing the thin film to obtain the low-dielectric-constant high-entropy thin film.

Preferably, Ba (Zr) is magnetron sputtered_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The ceramic target material in the film is BaCO₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂The powder and Me oxide powder are prepared by ball milling, presintering, granulating, molding and sintering, wherein the sintering temperature is lower than the system phase forming temperature by 100-200 ℃; la_0.7Sr_0.3The MnO target adopts a ceramic target purchased from mixed fertilizer family crystals.

Magnetron sputtering of Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Film and La_0.7Sr_0.3MnO₃In the process of buffering the layer: la_0.7Sr_0.3MnO₃Ceramic target material of buffer layer and Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃After the ceramic target material of the film is installed, pre-sputtering for 1-2 hours in a mixed gas atmosphere of argon and oxygen in a volume ratio of (3.9-4.1): 1 to remove impurities on the surface of the target material; then the deposition cavity of the magnetron sputtering system is vacuumized, and the vacuum degree is not less than 10^-5Pa; then introducing into the deposition chamberThe mixed gas of argon and oxygen ensures that the air pressure in the deposition chamber is 1.0-1.2 Pa; then SrTiO is added₃Baking the substrate at 600-650 deg.C under 1.0-1.2 Pa for 10-15 min to remove SrTiO₃A substrate surface attachment; then slowly introducing the mixed gas of argon and oxygen into the deposition cavity and adjusting the air pressure to be 1.0-1.2 Pa; then SrTiO₃Growing La on a substrate_0.7Sr_0.3MnO₃Buffer layer, then on La_0.7Sr_0.3MnO₃Growing Ba (Zr) on the buffer layer_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A film; ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃After the growth of the film is finished, annealing for 10-15 min under the air pressure of 1.0-1.2 Pa; and after the annealing is finished, taking out the sample when the temperature is reduced to the room temperature to obtain the low-dielectric-constant high-entropy film.

Preferably, La_0.7Sr_0.3MnO₃The thickness range of the buffer layer is 50-60 nm, Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The thickness of the film is 100 to 400 nm.

Preferably, Me is Y, Nb, Ta, V, Mo or W.

Preferably, SrTiO₃Single crystal SrTiO with substrate grown in (001) orientation₃A substrate.

The invention has the following beneficial technical effects:

the low-dielectric-constant high-entropy film has the dielectric constant as low as 1.102, is comparable to the current commercial material (k is 2.7), has no pores, has a compact structure, has high mechanical strength, is not easy to absorb water, and can greatly prolong the service life of an integrated circuit.

Drawings

Fig. 1 is a schematic diagram of an inter-row capacitor in two parallel line structure.

FIG. 2 shows Ba (Zr) according to the present invention_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Theta-2 theta scan of the film.

FIG. 3 shows Ba (Zr) according to the invention_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Dielectric constant and dielectric loss of the film are shown.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings and examples.

The low dielectric constant high entropy film of the invention comprises SrTiO₃Substrate and substrate placed on SrTiO₃La of substrate surface_0.7Sr_0.3MnO₃A buffer layer and a thin film on the buffer layer, the thin film comprising Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Film of Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A film is arranged on the La_0.7Sr_0.3MnO₃A buffer layer on the SrTiO₃A substrate surface. Wherein Me is Y, Nb, Ta, V, Mo or W, and the corresponding valence is Y³⁺、Nb⁵⁺、Ta⁵⁺、V⁵⁺、Mo⁶⁺And W⁶⁺。La_0.7Sr_0.3MnO₃The thickness range of the buffer layer is 50-60 nm, and the thickness of the buffer layer is Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The thickness of the film is 10 to 500 nm. SrTiO₃Single crystal SrTiO with substrate of (001) orientation growth₃A substrate. The Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The single crystal epitaxial film has the characteristics of low dielectric constant and low dielectric loss.

The preparation process of the low-dielectric-constant high-entropy film comprises the following steps:

(1) firstly according to the chemical formula Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Respectively weighing appropriate amount of 4-5N-grade BaCO₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂High purity powder of powder and Me oxide, ball milling the mixture of the high purity powderPre-sintering, granulating, forming and sintering processes, and preparing Ba (Zr) by adopting the traditional solid-phase ceramic preparation process_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A ceramic target material. In the process of preparing the ceramic target, the sintering temperature is 100-200 ℃ lower than the system phase forming temperature.

(2) Polishing the prepared ceramic target material by using sand paper, cleaning the surface by using an air gun, and then installing the ceramic target material into a magnetron sputtering system, wherein the volume ratio of the ceramic target material to the air gun is (3.9-4.1): 1, under the environment of room-temperature sputtering, firstly carrying out pre-sputtering for 1-2 h to remove impurities on the surface of the ceramic target.

(3) Selecting (001) oriented single crystal SrTiO₃Depositing a film on the substrate to form a SrTiO film₃Immersing the substrate into alcohol, washing for 3-10 min by oscillation by using ultrasonic cleaning equipment, and carrying out SrTiO washing₃The substrate is dried by nitrogen and then is immediately placed into a deposition cavity of a magnetron sputtering system.

(4) Pumping the air pressure in the deposition chamber to a higher vacuum degree by using a multistage air pumping system formed by combining a mechanical pump and a molecular pump, wherein the vacuum degree is not less than 10^-5Pa; introducing mixed gas of argon and oxygen required by the growth of the film into the deposition chamber, wherein the volume ratio of the argon to the oxygen in the mixed gas is (3.9-4.1): 1, and the pressure in the chamber is 1.0-1.2 Pa; then, the STO substrate is baked at 600-650 deg.C under 1.0-1.2 Pa for 10-15 min to remove the STO substrate (i.e. SrTiO)₃Substrate) surface attachment; and slowly introducing the mixed gas of argon and oxygen, and adjusting a mass flow meter to the required growth pressure of 1.0-1.2 Pa.

(5) After the air pressure is stabilized, the growth time is adjusted, and La grows on the STO substrate_0.7Sr_0.3MnO₃Buffer layer, high-entropy monocrystal epitaxial film growth is realized on the buffer layer, and compact Ba (Zr) can be grown by magnetron sputtering_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A film.

(6) After the growth is finished, annealing the sample for 10-15 min under the air pressure of 1.0-1.2 Pa; and after the annealing is finished, cooling the temperature to room temperature, and taking out the sample to obtain the high-entropy monocrystal epitaxial film with low dielectric constant and low dielectric loss.

Example 1

The preparation process of the low-dielectric-constant high-entropy film comprises the following steps:

(1) firstly according to the chemical formula Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Respectively weighing appropriate 4N-grade BaCO₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂Powder and Nb₂O₅High-purity powder of the powder, ball-milling, presintering, granulating, molding and sintering the mixture of the high-purity powder, and preparing the Ba (Zr) by adopting the traditional solid-phase ceramic preparation process_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A ceramic target material. In the process of preparing the ceramic target, the sintering temperature is 200 ℃ lower than the system phase forming temperature.

(2) Polishing the prepared ceramic target material by using sand paper, cleaning the surface by using an air gun, and then installing the ceramic target material into a magnetron sputtering system, wherein the volume ratio of the ceramic target material to the air gun is (3.9-4.1): 1, under the environment of room-temperature sputtering, firstly carrying out pre-sputtering for 2 hours to remove impurities on the surface of the ceramic target.

(3) Selecting (001) oriented single crystal SrTiO₃Depositing a film on the substrate to form a SrTiO film₃Immersing the substrate in alcohol, washing for 5min by shaking with ultrasonic cleaning equipment, and cleaning the SrTiO₃The substrate is dried by nitrogen and then is immediately placed into a deposition cavity of a magnetron sputtering system.

(4) Pumping the air pressure in the deposition chamber to a higher vacuum degree by using a multistage air pumping system formed by combining a mechanical pump and a molecular pump, wherein the vacuum degree is not less than 10^-5Pa; introducing mixed gas of argon and oxygen required by the growth of the film into the deposition chamber, wherein the volume ratio of the argon to the oxygen in the mixed gas is (3.9-4.1): 1, and the pressure in the chamber is 1.0-1.2 Pa; then, the STO substrate was baked at 650 ℃ under 1.01.2Pa for 10min to remove the STO₃A substrate surface attachment; slow downAnd introducing the mixed gas of argon and oxygen, and adjusting a mass flow meter to the required growth pressure of 1.0-1.2 Pa.

(5) After the air pressure is stabilized, the growth time is adjusted in STO₃Growing 50-60 nm La on the substrate_0.7Sr_0.3MnO₃And a buffer layer, and then growing the high-entropy monocrystal epitaxial thin film of 100nm on the buffer layer.

(6) After the growth is finished, annealing the sample for 10min under the air pressure of 1.0-1.2 Pa; and after the annealing is finished, cooling the temperature to room temperature, and taking out the sample to obtain the high-entropy monocrystal epitaxial film with low dielectric constant and low dielectric loss.

The low-dielectric-constant high-entropy film prepared by the embodiment is a single crystal epitaxial film with a perovskite structure, the dielectric constant value of the film can reach 1.102, the dielectric loss of the film is 0.044, and the film has good stability in the frequency range of 5 kHz-1000 kHz.

Example 2

The preparation process of the low-dielectric-constant high-entropy film comprises the following steps:

(1) firstly according to the chemical formula Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Respectively weighing appropriate 4N-grade BaCO₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂Powder and Nb₂O₅High-purity powder of the powder, ball-milling, presintering, granulating, molding and sintering the mixture of the high-purity powder, and preparing the Ba (Zr) by adopting the traditional solid-phase ceramic preparation process_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A ceramic target material. In the process of preparing the ceramic target, the sintering temperature is 150 ℃ lower than the system phase forming temperature.

(2) Polishing the prepared ceramic target material by using sand paper, cleaning the surface by using an air gun, and then installing the ceramic target material into a magnetron sputtering system, wherein the volume ratio of the ceramic target material to the air gun is (3.9-4.1): 1, under the environment of room-temperature sputtering, firstly carrying out pre-sputtering for 2 hours to remove impurities on the surface of the ceramic target.

(3) Selecting (001) oriented starchLong single crystal SrTiO₃Depositing a film on the substrate to form a SrTiO film₃Immersing the substrate in alcohol, washing the substrate for 10min by oscillation by ultrasonic washing equipment, and washing the washed SrTiO₃The substrate is dried by nitrogen and then is immediately placed into a deposition cavity of a magnetron sputtering system.

(4) Pumping the air pressure in the deposition chamber to a higher vacuum degree by using a multistage air pumping system formed by combining a mechanical pump and a molecular pump, wherein the vacuum degree is not less than 10^-5Pa; introducing mixed gas of argon and oxygen required by the growth of the film into the deposition chamber, wherein the volume ratio of the argon to the oxygen in the mixed gas is (3.9-4.1): 1, and the pressure in the chamber is 1.0-1.2 Pa; then, the STO substrate is baked at 630 ℃ under the air pressure of 1.0-1.2 Pa for 15min to remove the STO₃A substrate surface attachment; and slowly introducing the mixed gas of argon and oxygen, and adjusting a mass flow meter to the required growth pressure of 1.0-1.2 Pa.

(5) After the air pressure is stabilized, the growth time is adjusted in STO₃Growing 50-60 nm La on the substrate_0.7Sr_0.3MnO₃And a buffer layer, and then growing the 200nm high-entropy monocrystal epitaxial thin film on the buffer layer.

(6) After the growth is finished, annealing the sample for 15min under the air pressure of 1.0-1.2 Pa; and after the annealing is finished, cooling the temperature to room temperature, and taking out the sample to obtain the high-entropy monocrystal epitaxial film with low dielectric constant and low dielectric loss.

The low-dielectric-constant high-entropy film prepared by the embodiment is a single crystal epitaxial film with a perovskite structure, the dielectric constant value of the film can reach 1.963, the dielectric loss is 0.048, and the film has good stability in the frequency range of 5 kHz-1000 kHz.

Example 3

The preparation process of the low-dielectric-constant high-entropy film comprises the following steps:

(1) firstly according to the chemical formula Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Respectively weighing appropriate 4N-grade BaCO₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂Powder and Nb₂O₅High-purity powder of the powder, ball-milling, presintering, granulating, molding and sintering the mixture of the high-purity powder, and preparing the Ba (Zr) by adopting the traditional solid-phase ceramic preparation process_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A ceramic target material. In the process of preparing the ceramic target, the sintering temperature is 200 ℃ lower than the system phase forming temperature.

(2) Polishing the prepared ceramic target material by using sand paper, cleaning the surface by using an air gun, and then installing the ceramic target material into a magnetron sputtering system, wherein the volume ratio of the ceramic target material to the air gun is (3.9-4.1): 1, under the environment of room-temperature sputtering, firstly carrying out pre-sputtering for 1.5h to remove impurities on the surface of the ceramic target.

(3) Selecting (001) oriented single crystal SrTiO₃Depositing a film on the substrate to form a SrTiO film₃Immersing the substrate in alcohol, washing for 3min by shaking with ultrasonic cleaning equipment, and cleaning the SrTiO₃The substrate is dried by nitrogen and then is immediately placed into a deposition cavity of a magnetron sputtering system.

(4) Pumping the air pressure in the deposition chamber to a higher vacuum degree by using a multistage air pumping system formed by combining a mechanical pump and a molecular pump, wherein the vacuum degree is not less than 10^-5Pa; introducing mixed gas of argon and oxygen required by the growth of the film into the deposition chamber, wherein the volume ratio of the argon to the oxygen in the mixed gas is (3.9-4.1): 1, and the pressure in the chamber is 1.0-1.2 Pa; then, the STO substrate is baked at 620 ℃ under a pressure of 1.0 to 1.2Pa for 13min to remove the STO₃A substrate surface attachment; and slowly introducing the mixed gas of argon and oxygen, and adjusting a mass flow meter to the required growth pressure of 1.0-1.2 Pa.

(5) After the air pressure is stabilized, the growth time is adjusted in STO₃Growing 50-60 nm La on the substrate_0.7Sr_0.3MnO₃And a buffer layer, and then growing the 300nm high-entropy monocrystal epitaxial thin film on the buffer layer.

(6) After the growth is finished, annealing the sample for 13min under the air pressure of 1.0-1.2 Pa; and after the annealing is finished, cooling the temperature to room temperature, and taking out the sample to obtain the high-entropy monocrystal epitaxial film with low dielectric constant and low dielectric loss.

The low-dielectric-constant high-entropy film prepared by the embodiment is a single crystal epitaxial film with a perovskite structure, the dielectric constant value of the film can reach 3.307, the dielectric loss is 0.213, and the film has good stability in the frequency range of 5 kHz-1000 kHz.

Example 4

The preparation process of the low-dielectric-constant high-entropy film comprises the following steps:

(1) firstly according to the chemical formula Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃Respectively weighing appropriate amount of 5N grade BaCO₃Powder, ZrO₂Powder, TiO₂Powder, SnO₂Powder, HfO₂Powder and Nb₂O₅High-purity powder of the powder, ball-milling, presintering, granulating, molding and sintering the mixture of the high-purity powder, and preparing the Ba (Zr) by adopting the traditional solid-phase ceramic preparation process_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A ceramic target material. In the process of preparing the ceramic target, the sintering temperature is 200 ℃ lower than the system phase forming temperature.

(2) Polishing the prepared ceramic target material by using sand paper, cleaning the surface by using an air gun, and then installing the ceramic target material into a magnetron sputtering system, wherein the volume ratio of the ceramic target material to the air gun is (3.9-4.1): 1, under the environment of room-temperature sputtering, firstly carrying out pre-sputtering for 1h to remove impurities on the surface of the ceramic target.

(3) Selecting (001) oriented single crystal SrTiO₃Depositing a film on the substrate to form a SrTiO film₃Immersing the substrate in alcohol, washing for 5min by shaking with ultrasonic cleaning equipment, and cleaning the SrTiO₃The substrate is dried by nitrogen and then is immediately placed into a deposition cavity of a magnetron sputtering system.

(4) Pumping the air pressure in the deposition chamber to a higher vacuum degree by using a multistage air pumping system formed by combining a mechanical pump and a molecular pump, wherein the vacuum degree is not less than 10^～5Pa; then introducing mixed gas of argon and oxygen required by film growth into the deposition chamber, wherein the argon and the oxygen are contained in the mixed gasThe volume ratio of the gas is (3.9-4.1): 1, and the air pressure in the cavity is 1.0-1.2 Pa; then, the STO substrate is baked at 600 ℃ under an air pressure of 1.0 to 1.2Pa for 12min to remove the STO₃A substrate surface attachment; and slowly introducing the mixed gas of argon and oxygen, and adjusting a mass flow meter to the required growth pressure of 1.0-1.2 Pa.

(5) After the air pressure is stabilized, the growth time is adjusted in STO₃Growing 50-60 nm La on the substrate_0.7Sr_0.3MnO₃And a buffer layer, and then growing the high-entropy monocrystal epitaxial thin film with the thickness of 400nm on the buffer layer.

(6) After the growth is finished, annealing the sample for 12min under the pressure of 1.0-1.2 Pa; and after the annealing is finished, cooling the temperature to room temperature, and taking out the sample to obtain the high-entropy monocrystal epitaxial film with low dielectric constant and low dielectric loss.

The low-dielectric-constant high-entropy film prepared by the embodiment is a single crystal epitaxial film with a perovskite structure, the dielectric constant value of the film can reach 3.932, the dielectric loss of the film is 0.094, and the film has good stability in the frequency range of 5 kHz-1000 kHz.

The method adopts a radio frequency magnetron sputtering technology, and the La is obtained on the substrate by bombarding the target material by the plasma_0.7Sr_0.3MnO₃Buffer layer and Ba (Zr)_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The films with different thicknesses are obtained by adjusting the sputtering time of the target material, and the prepared film has lower dielectric constant and lower dielectric loss. Ba (Zr) of the invention_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The single crystal epitaxial film with low dielectric constant is prepared by adjusting different thicknesses under the condition of keeping the same components, and can be widely applied to various integrated circuits.

After the low dielectric constant film of the present invention was obtained, it was subjected to a structural test in which STO was grown₃Partially polishing the sample on the substrate buffer layer, plating a platinum electrode on a 200-mesh square copper mesh, and performingAnd (5) testing the dielectric property.

The properties of the obtained material are as follows:

fig. 1 is a schematic diagram of a structure of two parallel line capacitors. As in fig. 1, it can be seen that the two parallel line structures are embedded in a dielectric layer, the lines being insulated from the substrate (or the metal plane on top of the substrate) by a bottom dielectric layer. Line-to-line capacitors are more realistic structures than parallel plate capacitors, since they represent the capacitance between the interconnect lines due to technical limitations (minimum size, dielectric layer type, process conditions). Therefore, the performance of the low dielectric constant material has a significant effect on the performance of the overall capacitor.

As can be seen from fig. 2, the prepared films were single-crystal epitaxial films having orientations of (001), (002), (003), both of which were c-axis oriented, and no second phase appeared even in the thickest films.

Fig. 3 shows the dielectric constant and dielectric loss measured at room temperature for samples of different preparation schemes according to the present invention, and it can be seen that the film prepared according to the present invention has the lowest dielectric constant of 1.102 and the lowest dielectric loss of 0.056, which indicates that the high-entropy film according to the present invention has very low dielectric constant and dielectric loss.

The high-entropy film has the characteristics of low dielectric constant and low dielectric loss, can effectively improve the interconnection type of a circuit, reduces the conversion delay of the circuit, reduces leakage current and reduces power consumption. The high-entropy film belongs to a single-crystal lead-free film, avoids the harm of the traditional Pb-based film to the environment and human bodies, and meets the requirement of current industrial production on environmental protection.

Ba (Zr) provided by the invention_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The high-entropy monocrystal epitaxial film is prepared by bombarding target material with plasma on substrate by radio frequency magnetron sputtering technology to obtain La_0.7Sr_0.3MnO₃A buffer layer, and preparing Ba (Zr) on the buffer layer_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃A film. Firstly, high-purity powder is adopted and is transmitted by ceramicsSynthesizing Ba (Zr) by solid phase preparation process_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The ceramic target material is subjected to radio frequency magnetron sputtering technology, and the target material is bombarded by plasma under the conditions of high temperature and high oxygen pressure to realize epitaxial growth of a film on the substrate buffer layer; meanwhile, the thickness is controlled by adjusting the sputtering time of the target material, so that the performance of the film is predicted and regulated, the dielectric property of the film reaches a new minimum value, and the film is comparable to a Si-based low-dielectric-constant material.

The invention realizes films with different thicknesses by adjusting the sputtering time of the target material. Ba (Zr) is found by testing the dielectric property of the sample_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The dielectric constant of the sample is increased along with the increase of different thicknesses, but the total dielectric constant is kept between 1 and 5, and the requirement of low dielectric constant in an integrated circuit is met. Ba (Zr) of the invention_0.2Sn_0.2Ti_0.2Hf_0.2Me_0.2)O₃The advantages of single crystal epitaxial films are at least the following:

(1) the process is simple. The thin films with different thicknesses are grown only by controlling the preparation time, and the method has the advantages of simple structure and concise process.

(2) The frequency stability is good. It can be seen that the dielectric constant and dielectric loss of the sample are maintained at a relatively flat level as the frequency increases.

As noted above, without departing from the spirit and scope of the present invention. Many widely different embodiments may also be constructed. It should be understood that the invention is not limited to the specific examples described in the specification, except as defined in the appended claims.

(1) The preparation method has the advantages of simple operation, stable equipment performance, high preparation efficiency and high product qualification rate, and has good application and popularization.

(2) The reagents and starting materials of the invention are commercially available,

(3) most of the existing low-dielectric-constant materials have pores, the low-dielectric-constant materials have poor mechanical properties due to the existence of the pores, and the low-dielectric-constant high-entropy film provided by the invention has a compact structure.

(4) The low-dielectric-constant high-entropy film provided by the invention is free of volatile and harmful elements, stable in performance and environment-friendly.

(5) The low-dielectric-constant high-entropy film provided by the invention has better frequency stability,

(6) the low-dielectric-constant high-entropy film provided by the invention has better temperature stability due to the stability of the high-entropy material,

(7) more importantly, the principle of reducing the dielectric constant of the film material has the possibility of being expanded to other matrix and substrate materials, and based on the principle, the optimal low-dielectric-constant high-entropy film material which meets all performances in the field of microelectronics can be found.

The low-dielectric-constant high-entropy film provided by the invention enables the sample to form a compact structure, can form characteristics of low dielectric constant and low dielectric loss, can effectively improve the interconnection type of a circuit, reduces the conversion delay of the circuit, and simultaneously reduces leakage current and power consumption. The low-dielectric-constant high-entropy film provided by the invention has no volatile and harmful elements, avoids the harm of the traditional Pb-based film to the environment and human bodies, and meets the requirement of current industrial production on environmental protection.

The film provided by the invention has the advantages of low dielectric constant and low dielectric loss.