Magnetic-doped diamond thin film, preparation method and application thereof

Abstract

The application belongs to the field of thin film materials, and discloses a magnetic-doped diamond thin film and a preparation method and application thereof. The preparation method of the magnetic-doped diamond thin film comprises the following steps: taking hydrogen and methane as reaction precursors, taking an alloy containing a magnetic element (FePt alloy, CoPt alloy or NiPt alloy) as a hot wire material, and adopting a hot wire chemical vapor deposition method to prepare the magnetic-doped diamond thin film on the surface of a substrate. The alloy containing the magnetic element is used as the hot wire in the hot wire chemical vapor deposition process for the first time, the release and uniform doping of the magnetic element are realized through accurate control of the reaction atmosphere and temperature conditions, the ordered growth of the magnetic-doped diamond thin film and the stable release and uniform doping of the magnetic element are realized, and the magnetic-doped diamond thin film with good magnetic properties is obtained. The magnetic-doped diamond thin film increases the magnetism on the basis of keeping the diamond characteristics, has extremely high hardness, thermal conductivity and chemical stability, and can be applied to the development of multifunctional materials and the application in the fields of spintronics and sensors.

Description

Technical Field

[0001] This invention relates to the field of thin film materials technology, and in particular to a magnetically doped diamond thin film, its preparation method and application. Background Technology

[0002] Diamond films, with their excellent hardness, thermal conductivity, and chemical stability, are widely used in electronics, optics, and mechanics. However, pure diamond films lack magnetism, limiting their application in certain electronic and spintronics fields. Therefore, to endow diamond films with magnetism and enhance their multifunctionality, researchers have attempted to dope them with magnetic metal elements. Traditional chemical vapor deposition (CVD) can be used to synthesize high-quality diamond films, upon which magnetic metal elements can be doped. Currently common modification methods include microwave plasma CVD, but these still suffer from drawbacks such as demanding equipment requirements, high costs, and complex processes. Furthermore, existing methods for doping diamond films with magnetic metals can easily introduce impurities, leading to structural defects. In addition, the poor uniformity and controllability of the doped metal limit the application range and performance consistency of the films.

[0003] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to provide a magnetically doped diamond thin film, its preparation method and application, which aims to solve the problem that impurities are easily introduced into the diamond thin film during the process of doping magnetic metals in the prior art, resulting in structural defects in the diamond thin film.

[0005] The technical solution of the present invention is as follows:

[0006] In a first aspect, the present invention provides a method for preparing a magnetically doped diamond thin film, comprising: using hydrogen and methane as reaction precursors, using an alloy containing magnetic elements as a hot filament material, and preparing the magnetically doped diamond thin film on a substrate surface by hot filament chemical vapor deposition.

[0007] The alloy is a FePt alloy, a CoPt alloy, or a NiPt alloy.

[0008] Optionally, the volume percentage of methane in the reaction precursor is 0.5-2%.

[0009] Optionally, the magnetic element has a molar percentage of 50% in the alloy.

[0010] Optionally, the temperature of the hot wire material is 1200-1500℃.

[0011] Optionally, in the hot-filament chemical vapor deposition method, the growth rate of the magnetically doped diamond film is 1-2 μm / h. The present invention provides a faster growth rate of the magnetically doped diamond film than microwave plasma chemical vapor deposition.

[0012] Optionally, in the hot filament chemical vapor deposition method, the reaction pressure is 12-16 kPa and the reaction time is 1-5 hours.

[0013] Optionally, the substrate is a Si substrate, and the surface temperature of the substrate is 700-900℃.

[0014] In a second aspect, the present invention provides a magnetically doped diamond thin film, which is prepared by the method for preparing the magnetically doped diamond thin film.

[0015] Optionally, the doping rate of the magnetic element in the magnetic diamond film is 0.04%-0.2%.

[0016] The third invention provides an application of the magnetically doped diamond thin film described above in an electronic sensor.

[0017] Beneficial Effects: This invention is the first to use an alloy containing magnetic elements (FePt alloy, CoPt alloy, or NiPt alloy) as the hot filament material in a hot-filament chemical vapor deposition process. By precisely controlling the reaction atmosphere and temperature conditions, the orderly growth of magnetically doped diamond films and the stable release and uniform doping of magnetic elements are achieved, resulting in magnetically doped diamond films with excellent magnetic properties. The method of this invention is simple and the process is highly controllable. The prepared magnetically doped diamond films, while retaining the characteristics of diamond, not only have increased magnetism but also possess extremely high hardness, thermal conductivity, and chemical stability. Therefore, it is suitable for the development of multifunctional materials and applications in spintronics and sensors. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the hot-wire chemical vapor deposition apparatus used in the preparation of magnetically doped diamond thin films in Example 1 of the present invention.

[0019] Figure 2 This is a schematic diagram illustrating the growth mechanism of the magnetically doped diamond film prepared in Example 1 of the present invention.

[0020] Figure 3 The hysteresis loop is measured from the magnetically doped diamond thin film prepared in Example 1 of this invention. Detailed Implementation

[0021] This invention provides a magnetically doped diamond thin film, its preparation method, and its application. To make the objectives, technical solutions, and effects of this invention clearer and more explicit, the invention is further described in detail below. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention.

[0022] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the description of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0023] This invention provides a method for preparing a magnetically doped diamond film, comprising: using hydrogen and methane as reaction precursors, using an alloy containing magnetic elements as a hot filament material, and preparing the magnetically doped diamond film on a substrate surface by hot filament chemical vapor deposition.

[0024] The alloy is an FePt alloy, a CoPt alloy, or a NiPt alloy, meaning the magnetic element can be Fe, Co, or Ni.

[0025] In the method for preparing magnetically doped diamond thin films provided by this invention, when hydrogen and methane enter the cavity of the hot-wire chemical vapor deposition apparatus, they decompose into various groups at high temperature. Simultaneously, the magnetic element (denoted as M) is released from the alloy hot wire at high temperature, and is released as M, M... n Carbon diffuses to the substrate surface, and various functional groups flow on the substrate surface, seeking suitable reactive sites. As carbon atoms continue to diffuse and reach saturation on the substrate surface, atomic hydrogen terminates the surface chains, forming spk on the substrate surface. 2 sp 3 A mixed carbon film is formed. Subsequently, hydrogen radicals remove the non-diamond structural carbon, and the remaining active diamond carbon arranges to form a diamond crystal. Magnetic atoms may exist in the diamond crystal in a substitutional or interstitial manner during carbon atom diffusion and reaction, achieving stable release and uniform doping of magnetic elements in the diamond film, while avoiding the introduction of impurities. This results in a magnetically doped diamond film with excellent magnetic properties, extremely high hardness, thermal conductivity, and chemical stability. The method of this invention is simple, has high process controllability, and can effectively ensure the uniformity of magnetic element doping, thereby obtaining a magnetically doped diamond film with excellent magnetic and chemical stability.

[0026] In some embodiments, the volume percentage of methane in the reaction precursor is 0.5-2%. By adjusting the proportion of methane in the reaction precursor, the structure and doping effect of the magnetically doped diamond film can be affected, thereby obtaining different properties.

[0027] In some embodiments, the magnetic element has a molar percentage of 50% in the alloy.

[0028] In some embodiments, the temperature of the hot filament material is 1200-1500°C. By precisely controlling the reaction atmosphere and temperature conditions, orderly growth and uniform doping of the diamond film can be achieved.

[0029] In some embodiments, the growth rate of the magnetically doped diamond film in the hot-filament chemical vapor deposition method is 1-2 μm / h.

[0030] In some embodiments, the hot-filament chemical vapor deposition method uses a reaction pressure of 12-16 kPa and a reaction time of 1-5 hours. Within this reaction pressure and time range, high-quality magnetically doped diamond films can be grown.

[0031] In some embodiments, the substrate is a Si substrate, and the surface temperature of the substrate is 700-900°C.

[0032] This invention also provides a magnetically doped diamond film, which is prepared by the method described above.

[0033] In some embodiments, the doping rate of the magnetic element in the magnetically doped diamond film is 0.04%-0.2%.

[0034] This invention also provides the application of the magnetically doped diamond film in electronic sensors.

[0035] The following detailed description uses specific examples.

[0036] Example 1

[0037] In this embodiment, a NiPt alloy containing 50% Ni and 50% Pt is used as the hot wire. The silicon substrate is preheated to 800°C, and a hydrogen-methane mixture with a methane concentration of 2% is introduced into the cavity of the hot wire chemical vapor deposition (see schematic diagram of the device). Figure 1 As shown in the figure, the pressure was controlled at 16 kPa, the reaction temperature was 1400℃, and the deposition time was 5 hours to prepare the magnetically doped diamond film.

[0038] like Figure 2 As shown, after hydrogen and methane enter the cavity of the hot-wire chemical vapor deposition apparatus, they decompose into various functional groups at high temperatures. Simultaneously, Ni element is released from the NiPt alloy hot filament at high temperatures and diffuses to the substrate surface in the form of Ni and Ni3C. These functional groups flow on the substrate surface, seeking suitable reactive sites. As carbon atoms continue to diffuse and reach saturation on the substrate surface, atomic hydrogen terminates the surface chains, causing sp2+ formation on the substrate surface. 2 sp 3A mixed carbon film is formed. Subsequently, hydrogen radicals remove the non-diamond structure carbon, and the remaining active diamond carbon arranges to form a diamond crystal. Ni atoms may exist in the diamond crystal in a substitutional or interstitial manner during carbon atom diffusion and reaction. The embodiments of the present invention achieve stable release and uniform doping of nickel as a magnetic element in the diamond film, and avoid the introduction of other impurities. Finally, a high-quality magnetically doped diamond film with magnetic properties, extremely high hardness, thermal conductivity and chemical stability is prepared.

[0039] The magnetically doped diamond film has a uniform composition and a relatively smooth surface. Characteristic peaks of Ni are visible in XRD, and typical hysteresis loops can be measured using a vibrating magnetometer, such as... Figure 3 As shown, this demonstrates that the magnetically doped diamond film possesses in-plane soft magnetism.

[0040] It should be understood that the application of the present invention is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A method for preparing a magnetically doped diamond thin film, characterized in that, include: The magnetically doped diamond film is prepared on a substrate surface using hydrogen and methane as reaction precursors and an alloy containing magnetic elements as the hot filament material via hot filament chemical vapor deposition. The alloy containing magnetic elements is an FePt alloy, a CoPt alloy, or a NiPt alloy. In the hot filament chemical vapor deposition method, the reaction pressure is 12-16 kPa, the reaction time is 1-5 hours, and the temperature of the hot filament material is 1200-1500℃. The volume percentage of methane in the reaction precursor is 0.5-2%; The molar percentage of magnetic elements in the alloy is 50%; In the hot-wire chemical vapor deposition method, the growth rate of the magnetically doped diamond film is 1-2 μm / h.

2. The method for preparing a magnetically doped diamond thin film according to claim 1, characterized in that, The substrate is a Si substrate, and the surface temperature of the substrate is 700-900℃.

3. A magnetically doped diamond thin film, characterized in that, It is prepared by the method for preparing magnetically doped diamond thin films according to any one of claims 1-2.

4. The magnetically doped diamond thin film according to claim 3, characterized in that, The doping rate of magnetic elements in the magnetically doped diamond film is 0.04%-0.2%.

5. The application of the magnetically doped diamond thin film as described in claim 3 or 4 in an electronic sensor.

Images