A method for preparing a TaN / Ta2O5 composite film by ALD and application thereof

Abstract

The application relates to the technical field of thin films, in particular to a method for preparing a TaN / Ta2O5 composite film by adopting ALD and application thereof, which comprises the following steps: substrate pretreatment: selecting a substrate, polishing and grinding the substrate, and then performing ultrasonic cleaning and blowing dry; the pretreated substrate is placed into an ALD chamber, vacuumizing, and then a TaN / Ta2O5 double-layer film is prepared by a composite alternating deposition process. A dense Ta2O5 film is grown on the surface of the TaN film, covers the surface, helps to resist corrosion medium erosion, effectively improves the corrosion resistance of the TaN, and further improves the stability and reliability of the TaN film in the corrosion medium.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin films, in particular to a method for preparing TaN / Ta2O5 composite film by ALD and application thereof. BACKGROUND

[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 seawater physicochemical properties, etc., greatly affecting their service life and safety, so corrosion resistance is crucial. One of the most common protection methods is to deposit a protective film or coating on the metal surface. Nitride, carbide, silicide, transition metal oxide and other protective ceramic coatings. Among these protective ceramic coatings, tantalum nitride (TaN) is widely used in corrosion-resistant coatings and other fields due to its strong oxidation and corrosion resistance, high hardness at high temperatures, good chemical stability and other characteristics. Many famous thin film deposition techniques, including physical vapor deposition (PVD) and chemical vapor deposition (CVD), are used to synthesize TaN thin films. Traditional deposition methods such as PVD thin films often have many inherent defects, including columnar structures, pinholes, pores, cracks and discontinuities, which can significantly affect their corrosion resistance and cannot accurately control the film thickness and uniformity. Compared with PVD-prepared corrosion-resistant films, ALD is more dense, has a lower preparation temperature, fewer defects, better adhesion, and can control whether the film is a multi-layer composite structure or a composite film without layering at the nanoscale. TaN thin films have self-passivation properties and can generate a very thin Ta2O5 layer in air, which can resist water vapor erosion to some extent, but this natural generation process is slow and poorly controllable. To further increase the corrosion resistance of TaN, a dense Ta2O5 film can be grown on its surface using ALD process, which can isolate the TaN surface from direct contact with corrosive media, effectively slowing down the corrosion reaction, and thus making TaN materials have better stability and service life in corrosive environments. Currently, there is a lack of research on the preparation of TaN / Ta2O5 composite films by ALD and their application in the field of corrosion protection.

[0003] In view of the above background, the present inventors have finally obtained the present application after long-term research and practice. SUMMARY

[0004] The present application aims to solve the problem of how to prepare TaN / Ta2O5 composite film by atomic layer deposition method to improve its corrosion resistance, and provides a method for preparing TaN / Ta2O5 composite film by ALD and application thereof.

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

[0006] S1, substrate pretreatment: select the substrate, polish and grind it, 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 polishing.

[0009] In step S2, the TaN / Ta2O5 composite film has 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 at a flow rate of 100 sccm and Ar as purge gas at a 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. After deposition, a TaN / Ta2O5 double-layer film is obtained.

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

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

[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, at 300 °C, with NH3 as co-reactant to deposit TaN on the substrate;

[0017] S222, 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. Three cycles are repeated to obtain TaN / Ta2O5 multilayer films.

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

[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 corrosion resistance of metal materials.

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

[0021] (1) The present invention uses atomic layer deposition (ALD) technology to prepare a composite anti-corrosion film. The composite film has excellent density. ALD technology involves the requirements of film growth, such as uniformity, consistency, low temperature processing, and precise thickness control. Therefore, the film prepared using this technology has good uniformity and density.

[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 substrate prepared in the comparative example;

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

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

[0028] The above and other technical features and advantages of the present invention are described in more detail below with reference to 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 films deposited by TBTDET and NH3. Figure 1 The TaN thin 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 later 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 films; wait for the temperature to stabilize, turn on the gas to stabilize the pressure in the chamber; after the pressure in the chamber stabilizes, open the source bottle and start coating; after the experiment is over, turn off the exhaust and heating, and take samples;

[0035] The specific parameters for TaN deposition are: TBTDET as the Ta source precursor, NH3 as the co-reactant at a flow rate of 100 sccm, and Ar as the purge gas at a flow rate of 400 sccm. Each ALD TaNx deposition cycle consists of four consecutive steps: a TBTDET pulse, followed by an Ar purge, an NH3 pulse, and finally an Ar purge. At 275°C, the TBTDET and NH3 pulse times were fixed at supersaturated 0.4s and 4s, respectively, with the Ar pulse durations being 10s after the precursor and 15s after the reducing gas, respectively. After 600 deposition cycles, the resulting TaN film thickness was 45.0nm ± 2nm.

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

[0037] Example 2

[0038] 1. Preparation of substrate: 200 mm x 200 mm x 5 mm 316L stainless steel was selected as the substrate, all samples were polished with 80-2000# sandpaper and then polished with a polishing cloth, then ultrasonic cleaned with acetone and alcohol for 10 min and blown dry, and placed in a glove box for standby;

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

[0040] The specific steps of deposition are as follows:

[0041] The substrate pre-processed in step (1) was placed into the ALD chamber through the glove box, and the chamber was closed. The chamber was vacuumed to ≤1.0 x 10 -3 Pa by molecular pump; the parameters for depositing TaN / Ta2O5 film were set, such as the above-mentioned parameters for depositing double-layer film; after the temperature was stabilized, the gas was opened to stabilize the gas pressure in the chamber; after the gas pressure in the chamber was stabilized, the source bottle was opened for film deposition; after the experiment was completed, the pumping and heating were turned off, and the sample was taken out;

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

[0043] 3. Corrosion performance test: The samples were tested for corrosion resistance using a Shanghai Chenhua CHI760E electrochemical workstation. The AC disturbance voltage sine wave signal amplitude was 10mV, the measurement frequency was 100kHz-10mHz, and the impedance data was fitted using ZSimpWin software. The working electrode was subjected to a potentiodynamic 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 using the extrapolation method. 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 later 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, as described in the above specific steps; after the temperature stabilizes, turn on the gas to stabilize the pressure in the chamber; after the pressure in the chamber stabilizes, open the source bottle for coating; after the experiment is completed, turn off the exhaust and heating, and take samples;

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

[0050] 3. Corrosion performance test: The samples were tested for corrosion resistance using a Shanghai Chenhua CHI760E electrochemical workstation. The AC disturbance voltage sine wave signal amplitude was 10mV, the measurement frequency was 100kHz-10mHz, and the impedance data was fitted using ZSimpWin software. The working electrode was subjected to a potentiodynamic 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 using the extrapolation method. 2 The sample in this example is recorded as TaN / Ta2O5- double layer.

[0051] Figure 2 The Nyquist plots for the films produced in Examples 1-3 and the substrate produced in the comparative example show that the three films exhibit distinct capacitive responses, with large and incomplete capacitance arcs. The larger the diameter of the Nyquist plot, the higher the impedance and the better the corrosion resistance. The TaN / Ta2O5 bilayer film has the largest semicircle diameter, indicating that the TaN / Ta2O5 bilayer film has a higher 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 films 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 later use.

[0057] 2. Corrosion performance test: The corrosion resistance of 316L stainless steel was tested using a Shanghai Chenhua CHI760E electrochemical workstation. The AC disturbance voltage sine wave signal amplitude 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 serves as a control group and is recorded as SUS316L.

[0058] Corrosion resistance research:

[0059] 3.5% NaCl solution was selected. The electrochemical impedance spectroscopy and polarization curve (Tafel) of the test sample were tested using a three-electrode system, 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 is performed at open circuit potential. The sample is immersed in the electrolyte for 1 hour to reach the OCP on the 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 perspective, 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. As can be seen from Table 1, 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 ). This indicates that TaN, TaN / Ta2O5 multilayer and double-layer coatings have good barrier properties compared to bare 316L stainless steel, among which TaN / Ta2O5 double-layer coating has the best corrosion resistance.

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

[0062] sample <![CDATA[Icorr(μA / cm 2 )]]> SUS316L 0.4173 TaN 0.1770 <![CDATA[TaN / Ta2O5-多层]]> 0.0234 <![CDATA[TaN / Ta2O5-双层]]> 0.0144

[0063] The above description is merely a preferred embodiment of the present invention and is intended to be illustrative rather than restrictive of the present invention. Those skilled in the art will appreciate that many changes, modifications, and even equivalents may be made to the present invention within the spirit and scope of the claims, all of which 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 it, 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, wherein the TaN / Ta2O5 composite film is a TaN / Ta2O5 double-layer film structure or a TaN / Ta2O5 multi-layer film structure; 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 at a flow rate of 100 sccm and Ar as purge gas at a flow rate of 400 sccm; S212, then H2O was used as a co-reactant to deposit Ta2O5 on the TaN film. The pulse times of TBTDET and H2O were fixed at 0.3 s and 0.02 s, respectively. The Ar pulse time was 10 s after the precursor and 20 s after the water vapor, respectively. After deposition, a TaN / Ta2O5 bilayer film was obtained. The deposition cycle for TaN deposition was 330, and the deposition cycle for Ta2O5 deposition was 450. The specific steps of depositing the TaN / Ta2O5 multilayer thin film structure are as follows: S221, Ta source precursor TBTDET, at 300 °C, with NH3 as co-reactant to deposit TaN on the substrate; S222, then use H2O as a co-reactant to deposit Ta2O5 on the TaN film, and fix the pulse time of TBTDET and H2O to 0.3 s and 0.02 s, where the Ar pulse time is 10 s after the precursor and 20 s after the water vapor, respectively. The cycle process is (110+150)×3 cycle: first deposit 110 cycles of TaN on the substrate, and then deposit 150 cycles of Ta2O5 on the TaN film. Three cycles are repeated to obtain TaN / Ta2O5 multilayer films.

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

3. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 1, wherein: In step S212, the thickness of the TaN / Ta2O5 double-layer film is 55.0 nm±2 nm.

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

5. The method for preparing a TaN / Ta2O5 composite thin film by ALD according to claim 1, wherein: In step S222, the thickness of the TaN / Ta2O5 multilayer film is 53.0 nm±2 nm.

6. A TaN / Ta2O5 composite thin film prepared by the preparation method according to any one of claims 1 to 5.

7. Use of the TaN / Ta2O5 composite film according to claim 6 in improving the corrosion resistance of metal materials.

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