CN104112562B - Sm-Co-based permanent-magnet thin film high in film-base binding force and preparation method thereof - Google Patents

Abstract

The invention provides a Sm-Co-based permanent magnet film with high film-base binding force, a buffer layer is between the Sm-Co-based permanent magnet film and the substrate, and the buffer layer is a two-layer structure, one layer is located with the The copper film layer on the surface of the substrate, and the other layer is a tungsten film layer located on the surface of the copper film layer, and the buffer layer can effectively improve the bonding force between the Sm-Co-based permanent magnet film and the substrate. Experiments have confirmed that the heat treatment temperature of the Sm-Co-based permanent magnet film with this structure has been greatly increased during the heat treatment process, and can be raised from the existing 600°C to 800°C to more than 900°C, even when the heat treatment temperature is as high as 1000°C It is still well combined with the matrix and does not appear to fall off.

Description

Sm-Co-based permanent magnetic thin film with high film-based binding force and preparation method thereof

technical field

The invention belongs to the technical field of permanent magnet films, and in particular relates to a Sm-Co-based permanent magnet film with high film-base bonding force in high-temperature heat treatment and a preparation method thereof. The Sm-Co-based permanent magnet film can withstand high temperatures of 1000°C During the heat treatment process, good film-base bonding force is maintained, and the magnetic properties of the permanent magnet film are not affected. The permanent magnet film is mainly suitable for the fields of magnetic micromachines and micromotors.

Background technique

Sm-Co-based permanent magnetic films deposited on the surface of silicon substrates (such as silicon substrates) have important applications in magnetic micro-electromechanical systems due to their high Curie temperature and good corrosion resistance. Generally, the Sm-Co-based permanent magnet thin film is in an amorphous state after being deposited on the surface of the substrate, and is transformed into a crystalline state after high-temperature heat treatment, thereby obtaining certain magnetic properties.

Generally, as the thickness of the Sm-Co-based permanent magnet film increases, the film-base binding force gradually weakens; in addition, due to the different thermal expansion coefficients of the Sm-Co-based permanent magnet film and the substrate, when the thickness of the Sm-Co-based permanent magnet film increases, The stress during the heat treatment of the film also gradually increases, which makes the film easy to fall off from the surface of the substrate, directly affecting the application of the film. Therefore, the thickness of the Sm-Co-based permanent magnet thin film actually used at present is on the order of microns.

Due to the Sm-Co-based film and the matrix material, the binding relationship between the film and the matrix may be only a pure physical combination, or there may be a strong chemical bond. Physical bonding includes van der Waals bonding and electrostatic bonding. The van der Waals force is generated by the mutual polarization of two substances. It is a short-range force, and when the distance between atoms increases slightly, it quickly tends to zero. Therefore, when the combination of the film and the substrate is realized by van der Waals force, the film-substrate bonding force is poor. Electrostatic bonding also has the problem of low bonding force. Compared with physical binding, the chemical binding force is larger, and the film-based binding effect is better, but it needs to form new compounds between the interfaces.

In order to improve the binding force of the film base, a current method is to set a buffer layer between the surface of the substrate and the Sm-Co-based permanent magnetic film. For example, the Chinese patent application with the application number CN201210200142.3 proposes to set a tungsten thin film layer with a thickness of 10nm to 200nm as a buffer layer between the surface of the substrate and the micron-scale Sm-Co-based permanent magnet thin film, which can improve the Sm-Co The adhesive force between the base permanent magnet thin film and the substrate keeps it from detaching from the substrate even after high-temperature annealing treatment at 750°C. However, experiments have verified that when the heat treatment temperature is further increased, for example, to 800°C, the Sm-Co-based permanent magnetic film will fall off, and when the heat treatment temperature is raised to 1000°C, the fall-off phenomenon is already very serious.

On the other hand, in order to give full play to the magnetic properties of Sm-Co-based permanent magnet thin films, a higher heat treatment temperature is often required. However, as mentioned above, due to the limitation of the bonding force of the film base, the heat treatment temperature of the current Sm-Co-based permanent magnet thin film is often limited to the range of 600°C to 800°C. The Co-based permanent magnet thin film appeared to fall off.

Contents of the invention

The technical purpose of the present invention is to provide a kind of Sm-Co base permanent magnet thin film for the above-mentioned Sm-Co base permanent magnet thin film that is positioned at substrate surface easily from substrate surface under higher heat treatment temperature, and this thin film and substrate The bonding force is strong, so the heat treatment temperature can be increased, and even when the heat treatment temperature is as high as 1000 ° C, it is still well bonded to the substrate without falling off.

The technical scheme adopted by the present invention to realize the above-mentioned technical purpose is: a kind of Sm-Co-based permanent magnet thin film with high film base bonding force, the described Sm-Co-based permanent magnet thin film is located on the surface of the substrate, and the described substrate and Sm -A buffer layer is between the Co-based permanent magnetic film, and the buffer layer is a two-layer structure, one layer is a copper film layer or a molybdenum film layer positioned on the surface of the substrate, and the other layer is a tungsten (W) film layer positioned on the surface of the copper film layer. ) film layer.

The substrate is not limited, including silicon wafers, Si/SiO ₂ substrates, aluminum oxide substrates, etc., preferably, the substrate is Si/SiO ₂ (100) substrates, that is, the surface has SiO ₂ Si (100) type substrate.

Preferably, the thickness of the Sm-Co-based permanent magnet thin film is 0.1 um-100 um, more preferably 0.5 um-50 um, more preferably 1 um-10 um.

Preferably, the thickness of the copper thin film layer or the thickness of the Mo molybdenum thin film layer is 5nm-100nm, more preferably 10nm-50nm;

Preferably, the thickness of the tungsten film layer is 30nm-500nm, more preferably 100nm-300nm.

The present invention also provides a method for preparing the above-mentioned Sm-Co-based permanent magnetic thin film with high film-based binding force, comprising the following steps:

Step 1: Using magnetron sputtering technology, using the copper target as the buffer layer target, sputtering deposits the copper film layer on the surface of the substrate material, and then using the tungsten target as the buffer layer target material, sputtering deposits the tungsten film layer on the surface of the copper film layer Floor;

Step 2: Using magnetron sputtering technology, using the Sm-Co-based composite material as a target, sputtering and depositing a Sm-Co-based permanent magnetic film on the surface of the tungsten film layer;

Step 3: heat-treat the Sm—Co-based permanent magnet thin film treated in step 2.

In the above preparation method, the heat treatment temperature in step 3 reaches above 900°C.

Preferably, the heat treatment time of step 3 in the above preparation method is 5 minutes to 120 minutes.

In summary, the present invention effectively improves the bonding of the Sm-Co-based permanent magnet film and the substrate by inserting a double-layer buffer layer composed of a copper film layer and a tungsten film layer between the substrate and the Sm-Co-based permanent magnet film. force. Experiments have confirmed that the heat treatment temperature of the Sm-Co-based permanent magnet film with this structure has been greatly increased during the heat treatment process, and can be raised from the existing 600°C to 800°C to more than 900°C, even when the heat treatment temperature is as high as 1000°C. It is well combined with the matrix and does not appear to fall off.

Description of drawings

Fig. 1 is the situation figure after the Sm-Co-based permanent magnet thin film sample A with the single-layer W buffer layer prepared in Comparative Example 1 is annealed at 800 ° C for 10 min;

Fig. 2 is the situation diagram of the Sm-Co-based permanent magnet thin film sample C with a single-layer W buffer layer prepared in Comparative Example 1 after annealing at 1000 ° C for 10 min;

Fig. 3 is a situation diagram of the Sm-Co-based permanent magnet thin film sample C with a double-layer buffer layer prepared in Example 1 of the present invention after annealing at 1000° C. for 10 minutes.

detailed description

The present invention will be further described below through the drawings and specific embodiments, but it does not mean to limit the protection scope of the present invention.

Comparative Example 1:

This example is a comparative example of Example 1 described below.

In the present embodiment, the substrate selects the Si(100) type substrate with 500nm thick SiO _on the surface, i.e. substrate Si/SiO _{2 (} 100), and the SiO substrate surface is a W buffer layer with a thickness of 300nm, and the W buffer layer The surface is a Sm-Co-based permanent magnetic film with a thickness of 2 μm.

The preparation method of the above-mentioned Sm-Co-based permanent magnet thin film with W buffer layer is as follows:

Using magnetron sputtering equipment, using high-purity Ar gas as the working gas, the background vacuum is better than 6.0×10 ^-6 Pa, the sputtering temperature is room temperature, and the sputtering pressure is 0.5Pa; the W target with a purity of 99.99% is used as W buffer layer target material, the substrate Si/SiO ₂ (100) was cleaned with acetone and dried with nitrogen gas, and then sputtered and deposited a W buffer layer on its surface. The W target power was 130W, the sputtering rate was 14nm/min, and about 21 Minutes to obtain a W buffer layer with a thickness of 300nm; then, use the Sm(Co,Cu,Fe,Zr) _x composite target as the sputtering target of the Sm-Co-based permanent magnetic film, and sputter Sm- on the surface of the W buffer layer. The Co-based permanent magnetic film is deposited with a sputtering power of 200W and a sputtering rate of 39nm/min for about 60 minutes, and the thickness of the Sm-Co-based permanent magnetic film is 2 μm.

The above-prepared Sm—Co-based permanent magnet thin film samples A, B, and C with W buffer layer were annealed at 800° C., 900° C., and 1000° C. for 10 minutes, respectively. As shown in Figure 1, the sample A annealed at 800°C has already appeared to fall off from the surface of the substrate. The exfoliation of sample B annealed at 900°C is more obvious. The shedding phenomenon of sample C annealed at 1000°C is very serious, as shown in Figure 2.

Example 1:

In the present embodiment, same as above-mentioned Comparative Example 1, the substrate selects the Si/SiO ₂ (100) of the substrate, the buffer layer is between the substrate and the Sm-Co-based permanent magnet film, and the thickness of the Sm-Co-based permanent magnet film is 2 μm. Different from the above comparative example 1, the buffer layer has a two-layer structure, one layer is a copper film layer with a thickness of 30nm on the surface of the substrate, and the other layer is a tungsten film layer with a thickness of 300nm on the surface of the copper film layer. film layer.

The above-mentioned preparation method of the Sm-Co based permanent magnet thin film with double-layer buffer layer is as follows:

Using magnetron sputtering equipment, using high-purity Ar gas as the working gas, the background vacuum is better than 6.0×10 ^-6 Pa, the sputtering temperature is room temperature, and the sputtering pressure is 0.5Pa; the W target with a purity of 99.99% is used as W buffer layer target material, the Cu target with a purity of 99.95% is the Cu buffer layer target material, the substrate Si/SiO ₂ (100) is cleaned with acetone and dried with nitrogen gas, and then the Cu buffer layer is deposited on the surface by sputtering, the Cu target power It is 100W, the sputtering rate is 15nm/min, and it is deposited for about 2 minutes to obtain a Cu buffer layer of 30nm; after the deposition is completed, a W buffer layer is deposited. The W target power is 1W, and the sputtering rate is 14nm/min, and it is deposited for about 21 minutes. Obtain a W buffer layer with a thickness of 300nm; then, use the Sm(Co, Cu, Fe, Zr) _x composite target as the sputtering target of the Sm-Co-based permanent magnetic film, sputter on the surface of the W buffer layer, and the sputtering power It is 200W, the sputtering rate is 39nm/min, and it is deposited for about 60 minutes to obtain a Sm-Co-based permanent magnetic thin film layer with a thickness of 2 μm.

The above-prepared Sm-Co-based permanent magnet thin film samples A, B, and C with Cu/W double-layer buffer layers were annealed at 800°C, 900°C, and 1000°C for 10 minutes, respectively. The results show that the samples A and B annealed at 800°C and 900°C are well bonded to the matrix without falling off. Even the sample C annealed at 1000°C is still well bonded to the matrix, and no shedding occurs, as shown in Figure 3.

Example 2:

In this embodiment, the structure of the Sm—Co-based permanent magnet thin film on the surface of the substrate is basically the same as that in Embodiment 1. The difference is that the thickness of the copper thin film layer is 100nm, the thickness of the tungsten thin film layer is 500nm, and the thickness of the Sm—Co-based permanent magnet thin film is 5 μm.

The above-mentioned preparation method of the Sm-Co based permanent magnet thin film with double-layer buffer layer is as follows:

Using magnetron sputtering equipment, using high-purity Ar gas as the working gas, the background vacuum is better than 6.0×10 ^-6 Pa, the sputtering temperature is room temperature, and the sputtering pressure is 0.5Pa; the W target with a purity of 99.99% is used as W buffer layer target material, the Cu target with a purity of 99.95% is the Cu buffer layer target material, the substrate Si/SiO ₂ (100) is cleaned with acetone and dried with nitrogen gas, and then the Cu buffer layer is deposited on the surface by sputtering, the Cu target power It is 100W, the sputtering rate is 15nm/min, and it is deposited for about 7 minutes to obtain a Cu buffer layer of 100nm; after the deposition is completed, the W buffer layer is deposited. The W target power is 130W, and the sputtering rate is 14nm/min, and the deposition is about 36 minutes. Obtain a W buffer layer with a thickness of 500nm; then, use the Sm(Co, Cu, Fe, Zr) _x composite target as the sputtering target of the Sm-Co-based permanent magnetic film, sputter on the surface of the W buffer layer, and the sputtering power It is 200W, the sputtering rate is 39nm/min, and the deposition takes about 128 minutes to obtain a Sm-Co-based permanent magnetic thin film layer with a thickness of 5 μm.

The above-prepared Sm-Co-based permanent magnet thin film samples with Cu/W double-layer buffer layers were annealed at 800°C, 900°C, and 1000°C for 10 min, respectively. The results show that the Sm-Co-based permanent magnet film is well bonded to the substrate after annealing at 800°C and 900°C without falling off, and even after annealing at 1000°C, it is still well bonded to the substrate without falling off.

Example 3:

In this embodiment, the structure of the Sm—Co-based permanent magnet thin film on the surface of the substrate is basically the same as that in Embodiment 1. The difference is that the thickness of the copper film layer is 10nm, the thickness of the tungsten film layer is 100nm, and the thickness of the Sm—Co-based permanent magnet film is 1 μm.

The above-mentioned preparation method of the Sm-Co based permanent magnet thin film with double-layer buffer layer is as follows:

Using magnetron sputtering equipment, using high-purity Ar gas as the working gas, the background vacuum is better than 6.0×10 ^-6 Pa, the sputtering temperature is room temperature, and the sputtering pressure is 0.5Pa; the W target with a purity of 99.99% is used as W buffer layer target material, the Cu target with a purity of 99.95% is the Cu buffer layer target material, the substrate Si/SiO ₂ (100) is cleaned with acetone and dried with nitrogen gas, and then the Cu buffer layer is deposited on the surface by sputtering, the Cu target power It is 100W, the sputtering rate is 15nm/min, it is deposited for about 1 minute, and the Cu buffer layer is 10nm; after the deposition is completed, the W buffer layer is deposited, the W target power is 130W, the sputtering rate is 14nm/min, and it is deposited for about 7 minutes. Obtain a W buffer layer with a thickness of 100nm; then, use the Sm(Co, Cu, Fe, Zr) _x composite target as the sputtering target of the Sm-Co-based permanent magnetic film, sputter on the surface of the W buffer layer, and the sputtering power It is 200W, the sputtering rate is 39nm/min, and it is deposited for about 30 minutes to obtain a Sm-Co-based permanent magnetic thin film layer with a thickness of 1 μm.

The above-prepared Sm-Co-based permanent magnet thin film samples with Cu/W double-layer buffer layers were annealed at 800°C, 900°C, and 1000°C for 10 min, respectively. The results show that the Sm-Co-based permanent magnet film is well bonded to the substrate after annealing at 800°C and 900°C without falling off, and even after annealing at 1000°C, it is still well bonded to the substrate without falling off.

The embodiments described above have described the technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention, and are not intended to limit the present invention. All within the scope of the principles of the present invention Any modifications and improvements made should be included within the protection scope of the present invention.

Claims (13)

1. have the Sm-Co base permanent magnet thin film of high film-base bonding force, described Sm-Co base permanent magnet thin film is positioned at substrate surface, it is characterized in that: between described substrate and Sm-Co base permanent magnet thin film is Buffer layer, the buffer layer is a two-layer structure, one layer is a copper film layer positioned on the surface of the substrate, and the other layer is a tungsten film layer positioned on the surface of the copper film layer; the substrate is a silicon wafer or Si/SiO ₂ substrates; The Sm-Co-based permanent magnet thin film is well combined with the matrix after the high-temperature annealing treatment above 900 DEG C, and no shedding phenomenon occurs. 2. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 1, characterized in that: the thickness of the copper film layer is 5nm-100nm. 3. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 2, characterized in that: the thickness of the copper film layer is 10nm-50nm. 4. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 1, characterized in that: the thickness of the tungsten film layer is 30nm-500nm. 5. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 1, characterized in that: the thickness of the tungsten film layer is 100nm-300nm. 6. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 1, characterized in that: the thickness of the Sm-Co-based permanent magnet film is 0.1 um-100 um. 7. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 1, characterized in that: the thickness of the Sm-Co-based permanent magnet film is 0.5um-50um. 8. The Sm-Co-based permanent magnet film with high film-base binding force according to claim 1, characterized in that: the thickness of the Sm-Co-based permanent magnet film is 1um-10um. 9. The Sm-Co based permanent magnet thin film with high film-substrate bonding force according to claim 1, characterized in that: said substrate is a Si/SiO ₂ (100) substrate. 10. The Sm-Co-based permanent magnet film with high film-base bonding force according to any one of claims 1 to 9, characterized in that: the heat treatment temperature of the Sm-Co-based permanent magnet film is 900 ℃ or more. 11. The method for preparing the Sm-Co-based permanent magnetic thin film with high film-based binding force according to any one of claims 1 to 9, characterized in that: comprising the steps of: Step 1: Using magnetron sputtering technology, using the copper target as the buffer layer target, sputtering deposits the copper film layer on the surface of the substrate material, and then using the tungsten target as the buffer layer target material, sputtering deposits the tungsten film layer on the surface of the copper film layer Floor; Step 2: Using magnetron sputtering technology, using the Sm-Co-based composite material as a target, sputtering and depositing a Sm-Co-based permanent magnetic film on the surface of the tungsten film layer; Step 3: heat-treat the Sm—Co-based permanent magnet thin film treated in step 2. 12. The method for preparing the Sm-Co-based permanent magnet thin film with high film-based bonding force according to claim 11, characterized in that: the heat treatment temperature in step 3 is above 900°C. 13. The method for preparing the Sm-Co-based permanent magnet thin film with high film-based bonding force according to claim 11, characterized in that: the heat treatment time of the step 3 is 5-120 minutes.