YIG film material-based microwave absorber and preparation method thereof
阅读说明：本技术 一种基于yig薄膜材料的微波吸收体及其制备方法 (YIG film material-based microwave absorber and preparation method thereof ) 是由 张雪峰 朱大鹏 谭向洋 石振 张鉴 于 2019-10-08 设计创作，主要内容包括：本发明属于电磁波吸收材料领域,具体涉及一种基于YIG薄膜材料的微波吸收体及其制备方法。所涉及的镀膜方法有射频磁控溅射、化学气相沉积、液相外延和脉冲激光沉积等；所涉及的吸波体是在基体表面沉积的一层薄膜材料。所述基体可以为硅基片、钆镓石榴石基片、玻璃基片、氧化镁基片的一种；所述薄膜可以为YIG单晶薄膜、掺杂的YIG薄膜、可移动磁畴的Gd:Ga:YIG薄膜的一种。本发明主要利用YIG靶材在基片上沉积YIG薄膜,所制备的YIG薄膜具有吸波频带宽、吸波性能好等优点,可广泛应用于吸波材料领域。(The invention belongs to the field of electromagnetic wave absorbing materials, and particularly relates to a YIG film material-based microwave absorber and a preparation method thereof. The related coating methods comprise radio frequency magnetron sputtering, chemical vapor deposition, liquid phase epitaxy, pulsed laser deposition and the like; the wave absorber is a layer of thin film material deposited on the surface of a substrate. The substrate can be one of a silicon substrate, a gadolinium gallium garnet substrate, a glass substrate and a magnesium oxide substrate; the thin film can be one of a YIG single crystal thin film, a doped YIG thin film and a Gd: Ga: YIG thin film of a movable magnetic domain. The method mainly utilizes the YIG target material to deposit the YIG film on the substrate, and the prepared YIG film has the advantages of wide wave-absorbing frequency band, good wave-absorbing performance and the like, and can be widely applied to the field of wave-absorbing materials.)
1. A preparation method of a microwave absorber based on a YIG film material is characterized by comprising the following steps:
step one, preparing the YIG target material by a solid-phase sintering method
Grinding YIG powder, pressing into a wafer by using a tablet machine, and sintering at the high temperature of 900 ℃ and 1200 ℃ in a muffle furnace for 3-5 hours to prepare a YIG target material;
step two, ultrasonic cleaning of the substrate
Cleaning the substrate with alcohol and deionized water; immersing a substrate into deionized water, and placing the substrate in an ultrasonic cleaning machine for ultrasonic treatment for 10-15 minutes; drying the cleaned substrate by using high-purity nitrogen;
thirdly, sputtering the YIG target material on the substrate by adopting a deposition coating method
Putting YIG target material on a target material frame, pasting the substrate on a substrate table, sending the substrate into a sputtering chamber, and vacuumizing the sputtering chamber to 8.5 multiplied by 10 by using a mechanical pump and a molecular pump-4Introducing gas below Pa, adjusting a gate valve, power supply power and gas flow to glow the target, then carrying out pre-sputtering for 5-10 minutes, and finally sputtering a YIG film on the Si sheet by adjusting power, target base distance and pressure parameters;
step four, annealing treatment is carried out on the YIG film
And putting the prepared YIG film into a tube furnace, annealing for 3-4h at 750-800 ℃ in the air, and taking out to convert the amorphous state of the YIG film into a crystalline state.
2. The method for preparing a YIG film material-based microwave absorber as claimed in claim 1, wherein in the first step, the diameter of the wafer is 45-50mm, and the thickness is 2-4 mm; the particle size of the YIG powder after grinding is 80-140 meshes.
3. The method for preparing a YIG thin film material-based microwave absorber according to claim 1 or 2, wherein in the second step, the substrate is a silicon substrate, a gadolinium gallium garnet substrate, a glass substrate or a magnesium oxide substrate; the drying temperature is 70-90 ℃ and the drying time is 4-5 min.
4. The preparation method of the YIG film material-based microwave absorber as claimed in claim 1 or 2, wherein in the third step, the sputtering power is 70W, the target base distance is 6-10 cm, and the pressure is 2 Pa-11 Pa; the gas is oxygen gas, nitrogen gas or argon gas.
5. The method for preparing a YIG thin film material-based microwave absorber as claimed in claim 3, wherein in the third step, the sputtering power is 70W, the target base distance is 6-10 cm, and the pressure is 2 Pa-11 Pa; the gas is oxygen gas, nitrogen gas or argon gas.
6. A microwave absorber based on YIG film material, characterized in that the microwave absorber is prepared by the method of any one of claims 1 to 5, and the YIG film raw material is Y2O3And Fe2O3The YIG film is a garnet type ferrite formed by stacking crystal grains, the crystal lattice is a body-centered cubic crystal lattice, and the type of the lattice group is Ia3d-Oh10The crystal grains contain Y3Fe5O12And (4) phase(s).
7. A YIG thin film material-based microwave absorber as claimed in claim 6, wherein said garnet-type ferrite is a ferrimagnetic ferrite material; the crystal grains are uniform and tightly stacked; the YIG film has a thickness of 100 nm.
8. A YIG film material-based microwave absorber as claimed in claim 6 or 7, wherein said YIG film has a microwave absorption coefficient of 0.15-0.25 and a reflection parameter of 0.1-0.2.
9. YIG-based film according to claim 6 or 7Microwave absorber of material, characterised in that the substrate has a coefficient of thermal expansion of 6 x 10-610X 10-6 ℃ below zero and a film thermal expansion coefficient of 8X 10-6The matching is good at-12X 10-6 ℃.
10. A YIG film material-based microwave absorber as claimed in claim 8, wherein said substrate has a coefficient of thermal expansion of 6 x 10-610X 10-6 ℃ below zero and a film thermal expansion coefficient of 8X 10-6The matching is good at-12X 10-6 ℃.
Technical Field
The invention belongs to the field of electromagnetic wave absorbing materials, and relates to a YIG film material-based microwave absorber and a preparation method thereof.
Background
With the development of microwave communication technology, ferrite applied to microwave devices such as isolators, phase shifters, circulators and the like has higher and higher requirements, and the requirements are good performance, light weight, low cost and the like. Yttrium Iron Garnet (YIG) as a typical garnet type ferrite has good gyromagnetic effect, and microwave devices such as circulators, phase shifters and the like can be prepared by utilizing the gyromagnetic effect. With the development of electronic information technology in recent years, people have increasingly demanded higher YIG and their application markets in the fields of mobile communication, radar systems, and the like have been expanding.
Dillon et al in Bell laboratories used the flux method to prepare YIG single crystals for the first time, and then have attracted great interest in YIG research. And then preparing the film on different substrates by adopting different methods, or doping other elements in the YIG to improve the performance of the YIG film. For example, CN201610107438.9 patent discloses a preparation method based on a highly doped yttrium iron garnet film directly grown on silicon, and CN201610865406.5 patent discloses a YIG band-stop filter based on a planar resonant coupling structure and a manufacturing method thereof.
For the traditional YIG film preparation method, the process is complex, the reaction conditions are harsh, the operation process is complicated, large-scale industrial production is difficult to carry out, and a plurality of problems exist in practical application. For the radio frequency magnetron sputtering technology, the operation is simple and easy to control, the prepared film is compact and uniform, the area is large, and strong binding force exists between the film and the substrate. The YIG film prepared by the method has good impedance matching, so that the electromagnetic wave energy can be converted into heat energy or other forms of energy; the YIG film sputtered by the radio frequency magnetron sputtering has good crystallinity. The characteristics ensure that the YIG film has good wave absorbing performance. Therefore, the good performance of the material plays an indispensable role in the preparation of microwave communication devices.
Disclosure of Invention
The invention aims to provide a microwave absorbing material based on a YIG film material and a preparation method thereof, wherein a YIG film is sputtered on a substrate by a coating technology, and then amorphous in the film is converted into a crystalline state by annealing. Meanwhile, the crystallinity of the YIG film can be adjusted and controlled by changing sputtering parameters.
A preparation method of a microwave absorber based on a YIG film material comprises the following steps:
step one, preparing the YIG target material by a solid-phase sintering method
Grinding YIG powder, pressing into a wafer by using a tablet machine, and sintering for 3-5 hours at the high temperature of 900-1200 ℃ in a muffle furnace to prepare a YIG target material;
step two, ultrasonic cleaning of the substrate
Cleaning the substrate with alcohol and deionized water; immersing a substrate into deionized water, and placing the substrate in an ultrasonic cleaning machine for ultrasonic treatment for 10-15 minutes; drying the cleaned substrate by using high-purity nitrogen;
thirdly, sputtering the YIG target material on the substrate by adopting a deposition coating method
Putting YIG target material on a target material frame, pasting the substrate on a substrate table, sending the substrate into a sputtering chamber, and vacuumizing the sputtering chamber to 8.5 multiplied by 10 by using a mechanical pump and a molecular pump-4Introducing gas below Pa to adjust a gate valve, power supply power and gas flow to glow the target, then carrying out pre-sputtering for 5-10 minutes, and finally sputtering a YIG film on the Si wafer by adjusting parameters of power, target base distance and pressure intensity;
step four, annealing treatment is carried out on the YIG film
And putting the prepared YIG film into a tube furnace, annealing for 3-4h at 750-800 ℃ in the air, and taking out to convert the amorphous state of the YIG film into a crystalline state. In the first step, the diameter of the wafer is 45-50mm, and the thickness of the wafer is 2-4 mm; the YIG powder has a particle size of 80-140 meshes after grinding.
In the second step, the substrate is a silicon substrate, a gadolinium gallium garnet substrate, a glass substrate or a magnesium oxide substrate; the drying temperature is 70-90 ℃ and the drying time is 4-5 min.
In the third step, the sputtering power is 70W, the target base distance is 6-10 cm, and the pressure is 2-11 Pa. The gas is oxygen gas, nitrogen gas or argon gas.
Microwave based on YIG film materialAn absorbent material of YIG film, wherein the YIG film is Y2O3And Fe2O3The YIG film is a garnet type ferrite formed by stacking crystal grains, the crystal lattice is a body-centered cubic crystal lattice, and the type of the lattice group is Ia3d-Oh10The crystal grains contain Y3Fe5O12And (4) phase(s).
The garnet-type ferrite is a ferrimagnetic ferrite material; the crystal grains are uniform and tightly stacked; the YIG film has a thickness of 100 nm.
The YIG film has a microwave absorption coefficient of 0.15-0.25 and a reflection parameter of 0.1-0.2. Coefficient of thermal expansion of the substrate (6 x 10)-6-10X 10-6 ℃ and the coefficient of thermal expansion of the film (8X 10)-6The match is good at-12X 10-6 ℃).
The invention has the beneficial effects that: the invention provides a YIG film material-based microwave absorbing material and a preparation method thereof, which can expand the construction scheme of a microwave absorber. Meanwhile, the YIG film microwave absorbing material has the advantages of simple preparation method and excellent wave absorbing performance, and the absorption intensity of the wave absorber to the microwave can be changed by changing the crystallinity of the YIG film, so that the efficient and adjustable microwave absorbing material is obtained.
Drawings
FIG. 1 is a schematic representation of the microwave absorbing material of the YIG film in the process of the present invention;
FIG. 2 is a scanning electron microscope image corresponding to the microwave absorbing material of the YIG film in the method of the present invention;
FIG. 3 shows the absorption rate of electromagnetic waves by YIG thin-film devices corresponding to the microwave absorbing material of YIG thin films in the method of the present invention.
In the figure: 100 a substrate; 101 film.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the following detailed description of the operation of the present invention is provided with reference to the accompanying drawings and specific examples. It should be understood that the specific examples described herein are for purposes of illustration only and are not intended to limit the scope of the present disclosure.