Electronic information industry has the characteristics of high technology content, large input-output ratio, high added value and obvious benefit. Electronic materials and components are important parts of electronic information manufacturing industry, which are in the front of the electronic information industry chain, supporting the operation and development of modern communication, information network technology, micro mechanical intelligent system, industrial automation and household appliances, as well as the operation and development of information industries such as the electric energy interconnection network composed of new energy vehicles, wind power, photovoltaic and intelligent grid.
With the global economy continuing to be depressed and domestic economic growth slowing, the electronic information industry remains stable growth rate. The data show that in 2019, the operating income of electronic information manufacturing industry above the scale of China increased by 4.5% year-on-year, reaching 11trillion yuan; The total profit increased by 3.1% year-on-year, approaching 520billion yuan. Among them, although China's electronic information manufacturing industry will continue to grow steadily in 2019, the growth intensity will slow down, and the profit of electronic materials and components industry will be significantly lower.
Rare earth is closely related to electronic information industry. Rare earth elements have special 4f layer electronic structure, which show many characteristics of light, electricity and magnetism. After nano-processing, rare earth elements have many new characteristics, such as small size effect, high specific surface effect, quantum effect, extremely strong photoelectric Magnetoacoustic property, superconductivity, high chemical activity, etc., and the comprehensive performance is greatly improved. Moreover, through doping or as raw materials, new electronic functional materials with different composition and variety of materials, such as semiconductor materials, optoelectronic materials, etc Magnetic materials, electronic functional ceramics, electric energy materials and electronic communication materials are indispensable parts of electronic information industry. These materials have been applied to many electronic components industry products, and have formed a certain industrial scale. Therefore, electronic information industry is an important end-user of rare earth.
From the perspective of application demand, sustainable development strategy and made in China 2025 have created new space for the development of electronic information industry, and the market demand for electronic functional materials is also increasing greatly. Because of the improvement of the performance of the application devices, the use of the electronic functional materials modified by rare earth, the use scenarios are enriched, and the rapid development of the electronic information industry is promoted. Therefore, the main direction of the whole industry is to develop electronic functional materials and devices, to expand the middle and high-end application of rare earth electronic functional materials, to give full play to the strategic value and supporting role of rare earth in the transformation of traditional industries, the development of emerging industries and national defense science and technology industries.
Electronic functional materials are one of the most important raw materials in electronic information industry. It is a material with physical effects such as electricity, magnetism, sound, light and heat, and can detect, transform, transmit, process and store information through these effects, including semiconductor materials, optoelectronic materials, magnetic materials, electronic functional ceramics materials, electrical energy materials, etc. Rare earth has been widely used in optoelectronic materials, magnetic materials and electrical energy materials. It has a wide application prospect in semiconductor materials and electronic functional ceramics.
The application of rare earth in semiconductor materials
1.1 semiconductor material overview
Semiconductor materials are the important basic materials for the manufacture of transistors, integrated circuits, power electronic devices and optoelectronic devices, which support the development of electronic information industries such as communication, computer, information home appliances and network technology, and also an important symbol of measuring the national economic development, scientific and technological progress and national defense construction level. At present, the main semiconductor materials are silicon (SI), gallium arsenide (GaAs), silicon carbide (SIC), gallium nitride (GAN).
In recent years, the third generation semiconductor materials represented by zinc oxide (ZnO), SiC and Gan have opened up a new situation in the semiconductor industry. This kind of material has wider band gap width, higher breakdown electric field, thermal conductivity, electron saturation rate and higher radiation resistance. Because of the performance required by the core device RF power amplifier of mobile base station, SiC, Gan materials and devices are of great significance for 5g communication.
1.2 study on rare earth doped semiconductor materials
The doping of rare earth elements in semiconductor materials mainly uses the characteristics of the rare earth ion 4f electrons to prepare the semiconductor luminescent materials. Secondly, due to the chemical activity of rare earth ions in rare earth elements, they play an important role in absorbing impurities, and thus can effectively improve the purity and integrity of the semiconductor materials.
The effective excitation of rare earth ions usually requires proper matrix materials, and oxides are ideal matrix materials, including oxide semiconductor. The preparation technology of rare earth doped oxide thin film is compatible with the integrated circuit manufacturing technology (CMOS). Therefore, it is of great significance to realize the electroluminescent devices of silicon based rare earth doped oxide thin films, which is of great significance to broaden the application scope of rare earth ion luminescence and develop the light source needed for silicon based optoelectronic integration.
Because of its excellent luminescent and catalytic properties, rare earth oxide Eu2O3 has been widely used in various modern devices in microelectronics and optoelectronic technology. As a special semiconductor material, rare earth oxide semiconductor not only has the advantages of rich spectral lines, high color purity and high luminous efficiency, but also has the similar luminescence mechanism with ZnO, Gan and other semiconductors due to its special 4f band. Moreover, due to the existence of 4f band, the electronic transition will produce the characteristic spectral lines of the corresponding rare earth elements, Instead of a wide band transition, the luminescent efficiency will not be limited by the quenching of rare earth ions concentration. Therefore, epitaxial growth of Eu2O3 film on silicon wafer can effectively solve the incompatibility between Gan, ZnO and Si substrate, and make the electroluminescent devices of silicon based Eu2O3 films perfectly compatible with silicon based CMOS technology.
1.3 thin magnetic semiconductor materials
The diluted magnetic semiconductor (DMS) based on spin electronics is a new type of semiconductor material which has both ferromagnetic and semiconductor properties after doping in semiconductor materials. The doping materials mainly include transition metal element (TM) or rare earth element ion (RE). DMS can make use of both the charge and spin properties of electrons, which has great advantages in magnetic, magneto-optical and magnetoelectric fields, and is a kind of spin electronic device material with great potential. The material has two degrees of freedom, electronic charge and electron spin. It can be used in spin electronic devices. It has a broad application prospect in memory, detector, sensor and optical transmitter.
2. application of rare earth in optoelectronic materials
Optoelectronic materials are used in the field of optoelectronic technology. They are used in the fields of information, energy and national defense, which are processed, stored and transmitted by photons and electrons. Optoelectronic materials are mainly divided into photoelectric functional crystal materials, optical fiber materials and display materials, among which rare earth is one of the important materials in laser and nonlinear crystal materials and scintillation crystal materials. Rare earth elements have many applications in optoelectronic field, which involves the generation, modulation, transmission, storage, display and other applications of optical information, such as solid-state laser, optical fiber and optical display, and so on.
2.1 photoelectric functional crystal material
Since the 21st century, optoelectronic functional crystal materials, as the key materials in the fields of microelectronics, optoelectronics, communications, aerospace and modern military technology, have been paid attention by all countries in the world. There are many kinds of photoelectric functional crystals. At present, some industrial scale of the optical functional crystals are mainly laser and nonlinear crystals, scintillator crystals, optical crystals (including windows, led substrate crystals) and other crystal materials.
Laser and nonlinear crystal
The key materials of solid-state laser have important applications in laser weapons, thermonuclear fusion, laser communication, laser processing, medical treatment and other fields. The commonly used laser crystals are nd:yag, yb:yag, nd:ggg, nd:yvo4, nd:yap, ti:al2o3, cr:al2o3, nd:ylif4, etc. China has made a series of breakthroughs in laser crystal research. The main technical indexes of laser crystals, such as nd:yag, nd:yvo4, have reached the international advanced level. The export quantity of nd:yvo4 laser crystal has accounted for one third of the international market, and has become a big country in production and export, but large-scale and high-quality YAG laser crystal materials, There is still a certain gap in the consistency of quality.
Nonlinear optical crystal is a research field with advantages and characteristics in the world. It is in the leading position in the field of visible, ultraviolet and deep UV nonlinear optical crystals, which has attracted worldwide attention and occupies a position in the field of new materials in the world. The common nonlinear optical crystals are BBO crystal, LBO crystal, KDP crystal, KTP crystal, KBBF crystal, LiNbO3, ZnGeP2, etc.
Scintillator crystal material
Scintillator crystal material is an important radiation detection material, and it has been widely used in high energy physics, nuclear medicine, safety inspection, environmental monitoring, geological exploration, oil logging, industrial CT and other fields. The commonly used scintillator crystals are nai:tl, csi:tl, l (y) so, BGO, labr3:ce, PbWO4, CdWO4, etc“ During the 13th five year plan, China will meet the needs of several hundred million yuan for new scintillator crystals and devices under the promotion of anti-terrorism security inspection, industrial nondestructive testing, and nuclear medical diagnosis and application of CT and pet. There is a great gap between the domestic and foreign new cerium activated scintillator crystals and devices. The scintillator crystals are still dominated by traditional NaI (TL), CSI (TL), which cannot meet the application requirements in many fields such as nuclear medical imaging and nuclear physics. The development of cerium activated new rare earth scintillator crystal is still in the stage of R & D or engineering application.
2.2 optical fiber materials
Fiber materials can be divided into two categories: communication fiber and special fiber. Optical fiber optic cable is the infrastructure of communication network. Optical fiber is the main application field of rare earth optical glass. Rare earth is mainly used in fiber communication for erbium-doped fiber amplifier, which has the advantages of wide gain, low noise, and compatibility with optical fiber optical system, which makes it a very suitable amplifier for multi node network. EDFA and EDFL have been widely used in various fields, including ultra high bit telecommunication transmission system, frequency measurement, spectrum and space communication.
Special fiber plays a great role in optical communication field, and rare earth doped special fiber plays an important role in other related fields. With the progress of technology, rare earth doped fiber has been developed greatly in recent years. Besides the commonly used er3+ as dopant, other rare earth ions, such as yb3+, tm3+, ho3+, nd3+, pr3+, eu3+, etc., are also used as dopants to make rare earth doped special optical fiber. Ytterbium doped fiber is one of the most concerned research hotspots in the field of rare earth doped special fiber, and it has been paid attention to as a laser medium.
Rare earth doped fiber can not only be used for optical signal amplification, but also for fiber laser and fiber sensor. At the same time, the application of various optical fiber devices and optoelectronic devices based on rare earth doping has also been extended from optical fiber communication to sensing, medical treatment, material processing and national defense.
3. application of rare earth in magnetic materials
Permanent magnet (also known as hard magnetic), soft magnetic and spin magnetic materials are important functional materials in information industry. Rare earth permanent magnet material is a very important magnetic functional material for the information industry. It has close relationship with all aspects of modern information industry such as telecommunication network, TV network, Internet and smart grid. Rare earth permanent magnet materials must be indispensable in some fields. Rare earth permanent magnet materials and rare earth permanent magnet oxygen materials are the electronic functional materials mainly used in electronic information industry.
3.1 rare earth permanent magnet materials
Rare earth permanent magnet materials are widely used in many fields such as information communication, consumer electronics, energy-saving appliances, wind power generation, new energy vehicles, artificial intelligence and aerospace, and become an indispensable functional material in production and life. The rare earth permanent magnet materials mainly include sintered NdFeB, bonded NdFeB, hot pressing / hot deformation NdFeB and sintered samarium cobalt. NdFeB material, as one of the most important application fields of rare earth materials, is one of the important basic materials supporting the modern electronic information industry, and is closely related to people's lives. As small as computer hard disk and optical disk drive, to automobile, generator, medical instrument, magnetic levitation train, permanent magnet materials are ubiquitous. It is because rare earth permanent magnet materials are widely used, and the size of many electronic products is further reduced and the performance is greatly improved, which adapts to the development trend of light, thin and small demand of electronic products.
The vibration motor and micro electroacoustic element horn, VCM and spindle motor of hard disk drive are all using high performance NdFeB magnets. Most of the drive motors used in various equipment related to the information industry, such as printers, soft hard disk drives, optical disk drives, fax machines, photocopiers, etc., are permanent magnet BLDCM. These permanent magnet BLDCMs all adopt NdFeB magnets with high performance, so the demand for rare earth permanent magnet materials is very large in office automation equipment.
The permanent magnetic resonance imaging equipment of modern medical equipment has replaced the ferrite permanent magnet by the latest NdFeB permanent magnet material. The magnetic field strength has doubled, the image clarity has also been greatly improved, and a large amount of raw materials are saved. At present, general electric and Siemens in Germany have nuclear magnetic resonance imaging equipment production bases in China.
With the rise of new energy sources such as wind energy and solar energy, rare earth permanent magnet materials have been widely used in these new energy generators. Rare earth permanent magnet motor has the characteristics of high efficiency, light weight, reliable operation, and almost covers all kinds of motors. The RE permanent magnet motor is developing in the direction of high power (high speed, high torque), high function and miniaturization. The application prospect of the motor variety and application field is also very optimistic.
The development and application of rare earth permanent magnet materials reflect the important development direction of strategic emerging industries in China, and it is one of the key points of high-tech industry in China. The rare earth permanent magnet industry is not only the fastest developing and largest industry in the field of rare earth application, but also the largest re consumption field.
3.2 rare earth permanent magnet oxygen material
Permanent magnet oxygen and soft magnetic materials have become the most productive functional materials in the magnetic material industry due to their wide application in electric and electrical and telecommunication technology. With the rapid development of electrical and electronic information industries such as automobile, electric bicycle, office automation equipment, communication and network, the demand of permanent magnet oxygen materials increases at a rate of 20% - 30% per year. Although the rare earth Nd Fe-B permanent magnet materials have excellent properties, it is an important research direction to improve the magnetic properties of the permanent magnet oxygen due to the high cost. Various additions to permanent ferrite