Method for preparing TaN / Ta2O5 composite film by ALD (atomic layer deposition) and application of TaN / Ta2O5 composite film

Abstract

The invention relates to the technical field of thin films, in particular to a method for preparing a TaN / Ta2O5 composite thin film through ALD and application of the TaN / Ta2O5 composite thin film, and the method comprises the following steps: base material pretreatment: selecting a base material, polishing and grinding the base material, and blow-drying the base material after ultrasonic cleaning; and putting the pretreated base material into an ALD chamber, vacuumizing, and preparing the TaN / Ta2O5 double-layer film through a composite alternate deposition process. A layer of compact Ta2O5 film grows on the surface of the TaN film and covers the surface to help the TaN film to resist corrosion of a corrosive medium, so that the corrosion resistance of TaN is effectively improved, and the stability and reliability of the TaN film in the corrosive medium are further improved.

Description

Technical Field

[0001] The present invention relates to the field of thin film technology, and in particular to a method for preparing a TaN / Ta2O5 composite thin film by adopting ALD and an application thereof. Background Art

[0002] The marine environment poses a serious corrosion threat to various marine engineering structures, equipment and other metal materials due to its high salinity, high humidity and complex and changeable physical and chemical properties of seawater, which greatly affects their service life and safety. Therefore, corrosion resistance is crucial. One of the most common protection methods is to deposit a protective film or coating on the metal surface. There are many protective ceramic coatings such as nitrides, carbides, silicides, transition metal oxides, etc. Among these protective ceramic coatings, tantalum nitride (TaN) is widely used in corrosion-resistant coatings and other fields due to its strong resistance to oxidation corrosion, high hardness at high temperatures, and good chemical stability. Many well-known thin film deposition techniques, including physical vapor deposition (PVD) and chemical vapor deposition (CVD), are used to synthesize TaN films. Traditional deposition methods such as PVD films usually have many inherent defects, including columnar structures, pinholes, pores, cracks and discontinuities. These defects will significantly affect its corrosion resistance, and the film thickness and uniformity cannot be accurately controlled. Compared with the anti-corrosion film prepared by PVD, ALD is more dense, has a lower preparation temperature, fewer defects, better bonding strength, and can control at the nanoscale whether the film is a multi-layer composite structure or a composite film that does not distinguish between hierarchical structures. TaN film has self-passivation characteristics and can generate an extremely thin Ta2O5 layer in the air, which can resist the erosion of water vapor to a certain extent, but this natural generation process is slow and poorly controllable. In order to further increase the corrosion resistance of TaN, the ALD process can be used to grow a dense Ta2O5 film on its surface, which can isolate the direct contact between the TaN surface and the corrosive medium, thereby effectively slowing down the occurrence of corrosion reactions, and thus making the TaN material have better stability and service life in a corrosive environment. At present, there is a lack of research on the use of ALD technology to prepare TaN / Ta2O5 composite films and apply them to the field of corrosion protection.

[0003] In view of the above background, the inventors of the present invention finally obtained the present invention after a long period of research and practice. Summary of the invention

[0004] The purpose of the present invention is to solve the problem of how to prepare TaN / Ta2O5 composite thin film by atomic layer deposition method, so as to improve its corrosion resistance, and provide a method for preparing TaN / Ta2O5 composite thin film by ALD and its application.

[0005] In order to achieve the above object, the present invention discloses a method for preparing a TaN / Ta2O5 composite film by ALD, comprising the following steps:

[0006] S1, substrate pretreatment: select the substrate, polish and grind the substrate, ultrasonically clean it and then blow dry it;

[0007] S2, placing the substrate pretreated in step S1 into an ALD chamber, evacuating the chamber, and depositing a TaN / Ta2O5 composite film.

[0008] In step S1, the substrate is a metal substrate (including but not limited to 304, 316 stainless steel, etc.), and 80-2000# sandpaper is used for grinding.

[0009] In step S2, the TaN / Ta2O5 composite film is a double-layer structure, and the specific steps of depositing the TaN / Ta2O5 double-layer film are as follows:

[0010] S211, Ta source precursor TBTDET, TaN deposition on substrate at 300 °C with NH3 as co-reactant, flow rate of 100 sccm, Ar as purge gas, flow rate of 400 sccm;

[0011] S212, then use H2O as a co-reactant to deposit Ta2O5 on the TaN film, and fix the pulse time of TBTDET and H2O to 0.3s and 0.02s, where the Ar pulse time is 10s after the precursor and 20s after the reducing gas, respectively, and a TaN / Ta2O5 double-layer film is obtained after deposition.

[0012] In the step S211, the deposition cycle of TaN is 330, and the deposition cycle of Ta2O5 is 450.

[0013] In the step S212, the thickness of the TaN / Ta2O5 double-layer film is 55.0nm±2nm.

[0014] In step S2, the vacuum is drawn to ≤1.0×10 -3 Pa.

[0015] In step S2, the TaN / Ta2O5 composite film is a multilayer film structure, and the specific steps of depositing the TaN / Ta2O5 multilayer film are as follows:

[0016] S221, Ta source precursor TBTDET, TaN deposition on substrate with NH3 as co-reactant at 300 °C;

[0017] S222, and then use H2O as a co-reactant to deposit Ta2O5 on the TaN film, and fix the pulse time of TBTDET and H2O to 0.3s and 0.02s, where the Ar pulse time is 10s after the precursor and 20s after the reducing gas, respectively. The cycle process is (110+150)×3cycle: first deposit 110 cycles of TaN on the substrate, and then deposit 150 cycles of Ta2O5 on the TaN film, and cycle three groups to obtain TaN / Ta2O5 multilayer films.

[0018] In the step S222, the thickness of the TaN / Ta2O5 multilayer film is 53.0nm±2nm.

[0019] The invention also discloses a TaN / Ta2O5 composite film prepared by the preparation method and the application of the TaN / Ta2O5 composite film in improving the anti-corrosion performance of metal materials.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] (1) The present invention uses an atomic layer deposition technology to prepare a composite anticorrosive film, and the composite film has good compactness. ALD technology involves the requirements of film growth, such as uniformity, consistency, low temperature treatment and fine thickness control. Therefore, the film prepared by this technology has good uniformity and compactness.

[0022] (2) The tantalum oxide (Ta2O5) in the present invention can further protect the TaN film from further corrosion, and the prepared TaN / Ta2O5 composite film can effectively improve the corrosion resistance of metal materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 In the figure, (a) is the saturation curve of TBTDET, (b) is the saturation curve of NH3, (c) is the ALD temperature window, and (D) is the relationship between the growth rate and deposition cycle of TaN films deposited by TBTDET and NH3;

[0024] Figure 2 Nyquist plots of the films prepared in Examples 1-3 and the substrates prepared in the comparative examples;

[0025] Figure 3 Bode amplitude diagrams of the films prepared in Examples 1-3 and the substrates prepared in the comparative examples;

[0026] Figure 4 Bode phase angle diagrams of the films prepared in Examples 1-3 and the substrates prepared in the comparative examples;

[0027] Figure 5The Tafer curves of the films prepared in Examples 1-3 and the substrates prepared in the comparative examples are shown in FIG. DETAILED DESCRIPTION

[0028] The above and other technical features and advantages of the present invention are described in more detail below in conjunction with the accompanying drawings.

[0029] Figure 1 In the figure, (a) is the saturation curve of TBTDET, (b) is the saturation curve of NH3, (c) is the ALD temperature window, and (d) is the relationship between the growth rate and deposition cycle of TaN film deposited by TBTDET and NH3. Figure 1 The TaN film deposition parameters were selected.

[0030] Example 1

[0031] 1. Prepare the substrate: Select 200mm×200mm×5mm 316L stainless steel as the substrate. All samples are polished with 80-2000# sandpaper and then polished with a polishing cloth. Then, they are ultrasonically cleaned with acetone and alcohol for 10 minutes, blown dry, and placed in a glove box for use.

[0032] 2. Deposition of TaN film:

[0033] The specific steps of deposition are:

[0034] Place the substrate pretreated in step (1) into the ALD chamber through a glove box and close the chamber. Use a molecular pump to evacuate the chamber to a vacuum of ≤1.0×10 -3 Pa; set the parameters for depositing TaN thin film; wait for the temperature to stabilize, turn on the gas to stabilize the air pressure in the chamber; after the air pressure in the chamber is stable, open the source bottle for coating; after the experiment is over, turn off the exhaust heating and take samples;

[0035] The specific parameters for depositing the TaN layer are: Ta source precursor TBTDET, NH3 as a co-reactant, flow rate of 100sccm, Ar as a purge gas, flow rate of 400sccm, and each ALD TaNx deposition cycle consists of four consecutive steps: TBTDET pulse, followed by Ar purge, then NH3 pulse, and then Ar cleaning. At 275°C, the pulse times of TBTDET and NH3 are fixed to 0.4s and 4s of supersaturation, where the Ar pulse time is 10s after the precursor and 15s after the reducing gas, respectively. The process thickness of the TaN film was tested under 600 deposition cycles, and the process thickness of the TaN film was 45.0nm±2nm.

[0036] 3. Corrosion performance test: The samples were tested for corrosion resistance using Shanghai Chenhua CHI760E electrochemical workstation. The amplitude of the AC disturbance voltage sine wave signal was 10mV, the measurement frequency was 100kHz-10mHz, and the impedance data was fitted using ZSimpWin software. The working electrode was subjected to a dynamic potential scan with a scan range of -0.8V-1.2V and a scan rate of 1mV / S. The self-corrosion current was calculated to be 0.117μA / cm by extrapolation. 2 , the sample in this example is denoted as TaN.

[0037] Example 2

[0038] 1. Prepare the substrate: Select 200mm×200mm×5mm 316L stainless steel as the substrate. All samples are polished with 80-2000# sandpaper and then polished with a polishing cloth. Then, they are ultrasonically cleaned with acetone and alcohol for 10 minutes, blown dry, and placed in a glove box for use.

[0039] 2. Deposition of TaN / Ta2O5 multilayer films:

[0040] The specific steps of deposition are:

[0041] Place the substrate pretreated in step (1) into the ALD chamber through a glove box and close the chamber. Use a molecular pump to evacuate the chamber to a vacuum of ≤1.0×10 -3 Pa; set the parameters for depositing TaN / Ta2O5 thin films, such as the above double-layer thin film deposition parameters; wait for the temperature to stabilize, turn on the gas to stabilize the air pressure in the chamber; after the air pressure in the chamber is stable, open the source bottle for coating; after the experiment is over, turn off the exhaust heating and take samples;

[0042] The specific parameters for depositing the TaN / Ta2O5 multilayer thin film structure layer are as follows: The specific parameters for depositing the TaN / Ta2O5 double-layer thin film structure layer are as follows: Ta source precursor TBTDET, at 300°C, use NH3 as a co-reactant to deposit TaN on the substrate, the parameters are as above; then H2O is used as a co-reactant to deposit Ta2O5 on the TaN film, and the pulse times of TBTDET and H2O are fixed to 0.3s and 0.02s, where the Ar pulse time is 10s after the precursor and 20s after the reducing gas, respectively. The cycle process is (110+150)×3cycle: first deposit 110 cycles of TaN on the substrate, then deposit 150 cycles of Ta2O5 on the TaN film, and repeat three groups. The process thickness of the TaN / Ta2O5 film is 53.0nm±2nm.

[0043] 3. Corrosion performance test: The samples were tested for corrosion resistance using Shanghai Chenhua CHI760E electrochemical workstation. The amplitude of the AC disturbance voltage sine wave signal was 10mV, the measurement frequency was 100kHz-10mHz, and the impedance data was fitted using ZSimpWin software. The working electrode was subjected to a dynamic potential scan with a scan range of -0.8V-1.2V and a scan rate of 1mV / S. The self-corrosion current was calculated to be 0.0144μA / cm by extrapolation. 2 The sample in this example is recorded as TaN / Ta2O5-multilayer.

[0044] Example 3

[0045] 1. Prepare the substrate: Select 200mm×200mm×5mm 316L stainless steel as the substrate. All samples are polished with 80-2000# sandpaper and then polished with a polishing cloth. Then, they are ultrasonically cleaned with acetone and alcohol for 10 minutes, blown dry, and placed in a glove box for use.

[0046] 2. Deposition of TaN / Ta2O5 double-layer film:

[0047] The specific steps of deposition are:

[0048] Place the substrate pretreated in step (1) into the ALD chamber through a glove box and close the chamber. Use a molecular pump to evacuate the chamber to a vacuum of ≤1.0×10 -3 Pa; set the parameters for depositing TaN / Ta2O5 multilayer films, such as the deposition parameters in the above specific steps; after the temperature is stable, turn on the gas to stabilize the air pressure in the chamber; after the air pressure in the chamber is stable, open the source bottle for coating; after the experiment is over, turn off the exhaust heating and take samples;

[0049] The specific parameters for depositing the TaN / Ta2O5 double-layer thin film structure are as follows: Ta source precursor TBTDET, at 300°C, TaN is deposited on the substrate using NH3 as a co-reactant, with the parameters as above; then H2O is used as a co-reactant to deposit Ta2O5 on the TaN film, and the pulse times of TBTDET and H2O are fixed at 0.3s and 0.02s, where the Ar pulse time is 10s after the precursor and 20s after the reducing gas, respectively. The cycle process is 330+450cycle: first deposit 330 cycles of TaN on the substrate, and then deposit 450 cycles of Ta2O5 on the TaN film. The process thickness of the TaN / Ta2O5 film is 55.0nm±2nm.

[0050] 3. Corrosion performance test: The samples were tested for corrosion resistance using Shanghai Chenhua CHI760E electrochemical workstation. The amplitude of the AC disturbance voltage sine wave signal was 10mV, the measurement frequency was 100kHz-10mHz, and the impedance data was fitted using ZSimpWin software. The working electrode was subjected to a dynamic potential scan with a scan range of -0.8V-1.2V and a scan rate of 1mV / S. The self-corrosion current was calculated to be 0.0234μA / cm by extrapolation. 2 The sample in this example is recorded as TaN / Ta2O5- double layer.

[0051] Figure 2 The Nyquist plots of the films obtained in Examples 1-3 and the substrate obtained in the comparative example show that in the Nyquist curve, the capacitance response of the three films is obvious, and the capacitance arc is large and incomplete. The larger the diameter obtained in the Nyquist plot, the higher the impedance and the better the corrosion resistance. The semicircle diameter of the TaN / Ta2O5 double-layer film is the largest, indicating that the TaN / Ta2O5 double-layer film has a larger impedance and better corrosion resistance.

[0052] Figure 3 The Bode amplitude diagrams of the films prepared in Examples 1-3 and the substrate prepared in the comparative example show that the TaN / Ta2O5 composite film exhibits a larger |Z| value and has higher corrosion resistance.

[0053] Figure 4 The Bode phase angle diagrams of the films prepared in Examples 1-3 and the substrates prepared in the comparative examples are shown in FIG. Figure 4 Collaboration Figure 3 It is verified that TaN / Ta2O5 composite film has high corrosion resistance

[0054] Figure 5 The Tafer curve diagram of the film prepared in Examples 1-3 and the substrate prepared in the comparative example shows that the TaN / Ta2O5 composite film has a lower self-corrosion current density. The self-corrosion current density Icorr can reflect the corrosion rate of the film in the solution. The smaller the self-corrosion current density Icorr of the film, the better the corrosion resistance of the film.

[0055] Comparative Example

[0056] 1. Prepare the substrate: Select 200mm×200mm×5mm 316L stainless steel as the substrate. All samples are polished with 80-2000# sandpaper and then polished with a polishing cloth. Then, they are ultrasonically cleaned with acetone and alcohol for 10 minutes, blown dry, and placed in a glove box for use.

[0057] 2. Corrosion performance test: The corrosion resistance of 316L stainless steel was tested using Shanghai Chenhua CHI760E electrochemical workstation. The amplitude of the AC disturbance voltage sine wave signal was 10mV, the measurement frequency was 100kHz-10mHz, and the impedance data was fitted using ZSimpWin software. The working electrode was subjected to a dynamic potential scan with a scan range of -0.8V-1.2V and a scan rate of 1mV / S. The self-corrosion current was calculated by extrapolation to be 0.4173μA / cm 2 The substrate of this example is a bare substrate without coating, which is used as a control group and is recorded as SUS316L.

[0058] Corrosion resistance study:

[0059] 3.5% NaCl was selected as the solution. The electrochemical impedance spectrum and polarization curve (Tafel) of the test sample were tested using a three-electrode system in the experimental process, in which the area of ​​the working electrode contacting the electrolyte was 0.1 cm 2 The reference electrode is a saturated silver chloride R0305 electrode, and the auxiliary electrode is a Pt electrode. The electrochemical impedance spectroscopy test was performed at open circuit potential, and the sample was immersed in the electrolyte for 1 hour to reach OCP on its surface.

[0060] The self-corrosion current density of the samples prepared in the comparative example and Examples 1-3 is shown in Table 1 below: From a kinetic point of view, the self-corrosion current density Icorr can reflect the corrosion rate of the film in the solution. The smaller the self-corrosion current density Icorr of the film, the better the corrosion resistance of the film. It can be seen from Table 1 that the Icorr values ​​of the three coatings of TaN, TaN / Ta2O5 multilayer and TaN / Ta2O5 double-layer structure are 0.1170μA.cm -2 、0.0234μA.cm -2 、0.0144μA.cm -2 Compared with the bare substrate Icorr (0.4173μA.cm -2 ) is lower than that of bare 316L stainless steel. This shows that TaN, TaN / Ta2O5 multilayer and double-layer structure coatings have good barrier effects compared with bare 316L stainless steel, among which TaN / Ta2O5 double-layer structure coating has the best corrosion resistance.

[0061] Table 1 Self-corrosion current density of the prepared samples in comparative example and embodiment 1-3

[0062] sample <![CDATA[Icorr(μA / cm 2 )]]> SUS316L 0.4173 T N 0.1770 <![CDATA[TaN / Ta2O5 - Multilayer]]> 0.0234 <![CDATA[TaN / Ta2O5 - bilayer]]> 0.0144

[0063] The above description is only a preferred embodiment of the present invention, which is only illustrative and not restrictive of the present invention. Those skilled in the art understand that many changes, modifications, and even equivalences may be made to the present invention within the spirit and scope defined by the claims of the present invention, but all of them will fall within the scope of protection of the present invention.

Claims

1. A method for preparing TaN / Ta2O5 composite thin film by ALD, characterized in that: The following steps are involved: S1, substrate pretreatment: select the substrate, polish and grind the substrate, ultrasonically clean it and then blow dry it; S2, placing the substrate pretreated in step S1 into an ALD chamber, evacuating the chamber, and depositing a TaN / Ta2O5 composite film.

2. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 1, characterized in that: In the step S1, the substrate is a metal substrate, and 80-2000# sandpaper is used for grinding.

3. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 1, characterized in that: In step S2, the TaN / Ta2O5 composite film is a TaN / Ta2O5 double-layer film structure, and the specific steps of depositing the TaN / Ta2O5 double-layer film are as follows: S211, Ta source precursor TBTDET, TaN deposition on substrate at 300 °C with NH3 as co-reactant, flow rate of 100 sccm, Ar as purge gas, flow rate of 400 sccm; S212, then use H2O as a co-reactant to deposit Ta2O5 on the TaN film, and fix the pulse time of TBTDET and H2O to 0.3s and 0.02s, where the Ar pulse time is 10s after the precursor and 20s after the reducing gas, respectively, and a TaN / Ta2O5 double-layer film is obtained after deposition.

4. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 3, characterized in that: In the step S211, the deposition cycle of TaN is 330, and the deposition cycle of Ta2O5 is 450.

5. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 3, characterized in that: In the step S212, the thickness of the TaN / Ta2O5 double-layer film is 55.0nm±2nm.

6. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 1, characterized in that: In step S2, the vacuum is drawn to ≤1.0×10 -3 Pa.

7. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 1, characterized in that: In step S2, the TaN / Ta2O5 composite film is a multilayer film structure, and the specific steps of depositing the TaN / Ta2O5 multilayer film are as follows: S221, Ta source precursor TBTDET, TaN deposition on substrate with NH3 as co-reactant at 300 °C; S222, and then use H2O as a co-reactant to deposit Ta2O5 on the TaN film, and fix the pulse time of TBTDET and H2O to 0.3s and 0.02s, where the Ar pulse time is 10s after the precursor and 20s after the reducing gas, respectively. The cycle process is (110+150)×3cycle: first deposit 110 cycles of TaN on the substrate, and then deposit 150 cycles of Ta2O5 on the TaN film, and cycle three groups to obtain TaN / Ta2O5 multilayer films.

8. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 7, characterized in that: In the step S222, the thickness of the TaN / Ta2O5 multilayer film is 53.0nm±2nm.

9. A TaN / Ta2O5 composite film obtained by the preparation method according to any one of claims 1 to 8.

10. Use of the TaN / Ta2O5 composite film as claimed in claim 9 in improving the corrosion resistance of metal materials.

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