Zhengzhou Abrasives Grinding Research Institute Wang Guangzu Huazhong Diamond Tools Manufacturing Co., Ltd. Wang Wei 1. Introduction Chemical vapor deposition CVD diamond film is a completely different method from the former two methods after dynamic and static synthesis of diamond. According to the traditional diamond synthesis mechanism, it is incredible to synthesize diamonds in this way. However, it is an indisputable fact that diamonds have been synthesized in this way. Materials scientists predict that CVD diamond film will become the mainstream of diamond materials in the future development, not only can bring huge economic benefits, but more importantly, CVD film will be able to apply the full range of diamond materials to the extreme, such as machining, Key materials in the automotive, information, and energy sectors, as well as defense, military weapons, and cutting-edge technologies. The preparation and application of diamond films has become an important research direction in the field of thin film materials. At present, the annual market share of global CVD diamond film is about 1 billion US dollars, and the annual growth rate is more than 20%. In the next 20 years, it is entirely possible to develop a market of 10 billion US dollars per year [1]. Element Six Company is mainly based on microwave plasma growth (MPCVD), which mainly provides high-power density electronic device heat sink (Heat sink, Heat spreader), wheel dressing strip (CDD) and cutting tool diamond sheet (CDM, CDE). And CVD diamond single crystal. SP3 of the United States is mainly based on hot filamaent CVD. It mainly produces CVD diamond film coating tools, and also does some thick film cutters and grinding wheel trimming strips. China Beijing Tiandi Oriental Superhard Material Co., Ltd., the main growth technology is hot wire CVD diamond technology, its growth technical indicators are: growth rate ≥ 10μm / h, growth area Φ ≥ 150mm, success rate ≈ 100%. The process characteristics are reflected in reasonable straight wire drawing technology, DC plasma composite growth technology, oxygen-containing carbon source supply system, and automatic control technology for growth process. Thereby, the realization of advanced indicators of industrial growth technology can be guaranteed. It is worth mentioning that the application of CVD diamond wheel dressing tools has been widely recognized in developed countries such as Europe and the United States. The current representative CVD diamond growth techniques are large area hot filament CVD techniques and high power (35 kW or higher) microwave CVD techniques. The large-area hot wire CVD technology is widely used and relatively mature industrial technology, and its growth area has reached more than 300mm in diameter. Another representative industrial production technology is high-power (60 kW) microwave technology. The diamond diaphragm prepared by this technology has a diameter of 150 mm and a thickness of 2 mm, and its quality and quality of natural diamond are almost identical. 2. The main technical characteristics of CVD diamond film Why CVD diamond film will cause great concern to material technology engineers, which must be analyzed by its technical characteristics. Studies have confirmed that the hardness, thermal conductivity, density, elasticity (characterized by Young's modulus) and light transmission physical properties of high-quality diamond polycrystalline films have reached or are close to natural diamond. Table 1 The main physical properties of natural diamond and CVD diamond films* are the highest in all known substances** account for two of all known substances. 3. Diamond's position in science and technology Diamond is God's gift to mankind, Its unparalleled nature is a great achievement in the material world. As early as centuries ago, diamonds were the king of gems because of their beauty. Other superior properties of diamonds are also standing out in the material world. The instant heat dissipation characteristics of diamond have made it an ideal heat sink for high-power electronics such as LEDs or lasers. Diamond has no retained light transmission capability, making it the best of the window (such as infrared night vision goggles or radome). The ability of diamond to transmit sound at high frequencies makes it the material of choice for loudspeaker diaphragms. The potential of diamond to discharge at low electric fields will make it a dark horse for field emitters [2]. The human compatibility of diamonds also makes it the most biomedical material (such as heart valve or artificial joint coating). The high hole mobility of diamonds can even make it a semiconductor throne in the future [3]. The high-performance applications of diamonds are endless. The market for high-performance diamond films will be even larger in the future, so the growth of industrial diamonds will accelerate. After the popularity of diamond products in the future, it is very likely to raise the human material civilization to an unprecedented level. Since the nature of other materials cannot exceed diamonds, humans will enter the eternal “diamond eraâ€. 4. The king of CVD diamond film material 4.1 In semiconductor devices In recent years, plasma chemical vapor deposition has been used to synthesize single crystal diamond, ie semiconductor grade CVD diamond, with exceptionally high insulation and excellent current carrying. Comprehensive performance such as sub-mobility, so it is particularly attractive for high voltage and high frequency applications. There are potential market demands in the modern aerospace and automotive industries as well as transmission and distribution systems. The band gap, insulation (voltage resistance), carrier mobility, and thermal conductivity of semiconductor-grade CVD diamonds far exceed those of other semiconductor materials. See Table 2 [4] for details. Table 2 Thermal Performance of Semiconductor Grade CVD Diamond At present, the general insulation temperature limit for electrical equipment with long service life is 220 °C, and the temperature limit of future insulation materials should be at least 400 °C. It is difficult to reduce the weight and volume of the power electronic converter with the existing semiconductor technology and to integrate it compactly with the engine. Reducing the weight and volume of heat and cooling components in power electronics and allowing it to operate at high temperatures is critical to high temperature problems. Wide bandgap semiconductors such as CVD diamonds are capable of operating at much higher operating temperatures than currently used silicon power devices. Solid-state circuit devices fabricated from CVD diamonds, which have wide-bandgap materials, have advantages over silicon devices, making it possible to improve existing electrical designs and circuit layouts that affect the future of powertrains in the aerospace industry [5]. 4.2. Applications in Microwave Technology It is well known that microwave technology is widely used in measurement, radar, remote control, television, sky-astronomy, microwave spectroscopy, microwave relay communication, satellite communications, particle accelerators and other fields. It is worth noting that the diamond microwave transmission window is a key component of the ongoing nuclear fusion test in Germany and Japan. The diamond microwave transmission window developed by Element Six and the world's leading nuclear fusion research institutes can handle more than 1 MW of microwave power, which is more than twice as large as the transmission window of any other material. Since CVD diamond has low absorption of microwave energy, high thermal conductivity and low dielectric constant, it is a critical material in microwave applications. At present, the cooperation between DMD and INEX is studying the possibility of manufacturing metal semiconductor field effect transistors using single crystal CVD diamond produced by Element Six [6]. Metal-semiconductor field-effect transistors have long been considered one of the most promising devices made with XVD diamond. Because diamond has the ability to work at higher temperatures and higher breakdown pressures than conventional semiconductors. In addition to its extremely high hardness, thermal conductivity, breaking strength and good chemical inertness, diamond has attracted extensive attention due to its high dielectric strength and high hole electron mobility and wide bandgap. Because of the inherent inherent properties of single crystal CVD diamonds compared to competitive materials used in electronic circuits such as silicon and gallium arsenide, there is a strong demand for applications in high technology. DMD and the world's leading company, Filtronic, which designs and manufactures a wide range of microwave devices and subsystems, research new types of diamond devices in the high-tech strength of raw materials, semiconductor devices and circuit design to improve microwave power electronics, possibly resulting in microwave power electronics. Great changes in equipment. 4.3 Applications in Monitoring Devices and Detection Systems Diamond is an excellent material for manufacturing semi-transparent monitors in the X-ray energy range of 5 to 20 keV. The Synchrotron Radiation Laboratory of the European Synchrotron Radiation X-ray test was performed on a single crystal CVD diamond provided by Element Six. The results confirmed that the quality of single crystal CVD diamond produced by Element Six has reached the detector level [7]. In order to meet the market demand for various types of detectors, Element Six has specially established a holding subsidiary (Diamond Deteefors Led) to develop synthetic diamond for new detectors. The initial targets are determined by four major markets: high-energy physics, nuclear monitoring, radiotherapy dosimetry and far-infrared radiation detection [8]. 4.4 Applications in Optical Technology Diamond has excellent optical properties, which can pass all the light from ultraviolet light to visible light and infrared light, and is the only material with a wide range of far infrared (8~10μm) transmission range. It is not only strong in strength, but also has good resistance to scratches, corrosion and thermal shock, so it is widely used in the medical, communication, information storage and military sectors. 4.4.1 Application in optical communication systems [9]. The single crystal diamond standard block developed by Element Six is ​​a very accurate high-end filter for generating signals along the laser that is sent along the fiber. This diamond standard block filters narrow-wavelength light and can be used to increase the passband width, especially the passband width of the fiber optic backbone. The diamond standard block is a rectangular block cut by a single crystal CVD diamond along its two-point crystal orientation. The material is consistent, durable and not afraid of scratches. It has a high thermal conductivity and is not affected by temperature changes. 4.4.2 Applications in optical information storage technology In order to create files such as files, video information and graphics, there is an increasing need for a dense and large-capacity information storage method. Currently used optical discs such as DVDs have an information capacity of only 4.7 GB, while second-generation optical discs called Blu-Ray have an information storage capacity of 25 GB, but still cannot meet the needs of computer development. To increase the information capacity of the optical disc, it is necessary to increase the numerical aperture (NA) of the lens while reducing the laser wavelength. Among all UV-permeable materials, diamond has the highest refractive index. However, high temperature and high pressure synthetic diamond and ordinary CVD diamond are not suitable for the production of visible and ultraviolet optical devices because the former contains impurity nitrogen and the latter is polycrystalline. At the beginning of this century, Element Six developed a single CVD diamond for the manufacture of near-infrared (wavelength 0.75~2.5μm) and visible light devices. A high numerical aperture lens made of single crystal CVD diamond for near-field optical information storage can greatly increase the information capacity of an optical disk, and it is possible to increase it to 150 GB or more. The theoretical information capacity is said to be as high as 550GB [10]. 4.5 Spacecraft components utilize the high thermal conductivity and radiation resistance of diamond to deposit diamond film on some parts of the spacecraft, which can greatly improve the heat dissipation capability of the components, so that the components have thermal shock resistance and radiation resistance. The weight of the spacecraft is reduced, which also significantly reduces the launch cost. For example, a refrigeration system that currently accounts for 65% of the satellite's average weight will use a diamond film chip to reduce the weight by 90%, thereby reducing satellite launch costs to one-tenth of the previous. 4.6 New electronic components Diamond has the highest thermal conductivity and electrical resistivity of all materials. Using these characteristics of diamond, depositing nano-diamond film on the surface of electronic components can greatly reduce the size of components used for heat dissipation in original components. It solves the problem of heat conduction and also offers the possibility of making very large scale integrated circuits. The film layer also protects the conductor from insulation and avoids mutual interference between the components. 4.7 Missile Infrared Window The most commonly used infrared window materials are ZnS and ZnSe. Although these two materials have good infrared transmission ability, they are easily damaged. In military applications, the requirements for infrared windows are very strict. These devices often work under very harsh conditions. For example, the infrared window used for missiles not only runs at high speed after the missile is launched, but also withstands the test of wind, sand, rain and snow. The diamond film is a high-quality surface material, diamond has infrared anti-reflection properties, and the diamond film can be used as a good anti-reflection film material for the infrared window. In addition, the high thermal conductivity, wear resistance and other physical properties of diamond can also protect the infrared window from external impact. Therefore, the diamond film is coated on the surface of the infrared window, which completely solves various problems in the application of the infrared window in the military aerospace field. 4.8 Hard Disk Reader In the data storage industry, the hard disk has the highest technical content, and the hard disk read/write head is the core of the hard disk. In recent years, the bottleneck in increasing the density of media and the speed of reading and writing is precisely the distance between the head of the hard disk and the disk. In order to break the spacing limit and protect the head from damage, the only solution is to plate a diamond film with a thickness of only a few tens of angstroms (1 angstrom is equal to one tenth of a nanometer) on the surface of the head. The success of technology will be a qualitative leap in the data storage industry. 4.9 The trigger voltage is ~1V/μm. When the voltage is 4V/μm, a significant current density (4×10-4A/cm2) can be obtained. Therefore, nanodiamond can be applied to electron field emission. 4.10 Micro-electromechanical systems based on silicon have been successfully applied in medical, transportation, industrial and aerospace. However, silicon has a high friction coefficient and poor wear resistance, which cannot meet the material requirements of some high-speed moving parts. The nano-diamond crystal grain is extremely thin, has high surface smoothness, high hardness, good wear resistance and low friction coefficient, and is an ideal substitute material for silicon. 4.11 For surface acoustic wave devices (SAW), the surface acoustic wave velocity of nanodiamonds is similar to that of micron-sized diamonds, but the growth surface is smoother, which greatly reduces the processing cost [11]. 4.12 Ultra-precision tools The use of high-quality CVD diamond film with excellent performance instead of natural diamond to produce ultra-precision tools can reduce production costs, break the monopoly of foreign technology, and reduce the dependence of foreign technology on domestic precision processing. Ultra-precision tools are widely used in the military field for the machining of precision instruments such as aerospace instrument bearings, radar waveguides, optics, high-energy accelerators, etc. [12] Ultra-precision machining is the replacement of grinding and other grinding with high-efficiency machining. A high-precision machining technology, the annual value of ultra-precision machining tools consumed in aerospace and optical processing in China exceeds several million dollars, and it is growing. In terms of production technology, CVD diamond film can be used as the edge material of ultra-precision machining tools [13]. 4.13 Diamond film travels into space "In space, Shenzhen is closest to me, because the products of Shenzhen Leidi Company are worn on my head" - let Yang Liwei express such an emotion is the inconspicuous diamond film. Some people think that the diamond film is the greatest material invention since the advent of plastics. It is also the fifth-generation material that marks the progress of human civilization after the stone, bronze, iron and silicon [14]. 4.14 Entering the life of the citizens This new material is gradually entering the public life from the cutting-edge fields such as aerospace. For example, glasses, mobile phone windows, case boxes, cosmetic boxes, and car mirrors have begun to use such diamond film materials. Products coated with this kind of diamond film can enhance hardness, scratch resistance, anti-fog, anti-ultraviolet, etc. If applied to the rear mirror of the car, the mirror can be automatically cleaned, and the driver does not need to look down after the rain. Clear and troubled. 4.15 Large-scale development At present, diamond film solar hydrogen energy production equipment, diamond film solar sewage (exhaust gas) processing equipment has been successfully developed, diamond film flat panel display, diamond film high energy high density capacitor is also about to be launched. 4.16 Applied to Nano-Calculators Nano-mechanical chips are more durable than traditional silicon chips and can be used in extreme environments such as space and automotive engines. The low power consumption of the nanomechanical calculator not only extends the life of the notebook battery, but also operates at a high temperature of 500 °C. Blick said that the components of the nanometer calculator are probably not silicon, but an extremely hard diamond film. Through chemical processing, diamond films can be used in large-scale production of integrated circuits [15]. 4.17 Nano-diamond composite coating drawing die The nano-diamond coating drawing die developed by Shanghai Jiaotong University has been industrialized by Shanghai Dating Diamond Coating Co., Ltd. This drawing mold not only can greatly extend the service life of traditional molds (more than 10 times higher than cemented carbide molds), can significantly improve the quality and grade of cable products, effectively save copper and other raw materials, and reduce the national war resources. Consumption, improve the production efficiency of related industries, and obtain large economic benefits. For the mold industry itself, it can gradually realize the transition from labor-intensive, resource-consuming to high-tech and resource-saving, and improve China's drawing molds and wear-resistant products. The level and competitiveness in the international market to promote sustainable economic development is a successful example of using nanotechnology to transform traditional industries [16]. 5. Infinitely good future 5.1 In the early 1980s, CVD diamond film growth technology made breakthrough progress. After more than 20 years of research and development, there are currently four forms of CVD diamond, which are: (1) pure polycrystalline Diamond thick film; (2) coated diamond; (3) large single crystal diamond; (4) nano diamond film. It is believed that with the further development of CVD diamond and its downstream product technology research and the gradual reduction of production costs, its comprehensive performance and application will be realized [17,18]. 5.2 Materials scientists assert that CVD diamonds will become the mainstream of diamond materials in the future, and you should taste some delicious foods through the above brief description. Its development can not only bring huge economic and social benefits, but more importantly, CVD diamond will bring the full range of characteristics and applications of diamond materials to the extreme, and become the pillar industry of the national economy, such as processing industry, automobile. Key materials in the fields of information, energy, and defense, military weapons, and cutting-edge technologies have effectively changed the industrial structure of the overall national economy. 5.3 The industrialization of CVD diamond adds fresh blood to China's diamond industry, and makes up for the shortage of PCD and natural diamond materials and products in China's diamond industry. It has a profound impact on the development of diamond material industry and industrial structure, making China's diamond industry Technology and product structure have become reasonable and advanced. 5.4 The in-depth study of high-quality nano-diamond film preparation technology is a prerequisite for realizing nano-diamond film microstructure control, performance testing, identification technology research and accurate theoretical analysis, and is also the basis of all practical applications. 5.5 Due to its application prospects, after nearly a decade of high-temperature superconductivity, diamond film heat has been set up around the world, making diamond development into a new era. Materials experts have hailed it as the most important material since plastics. The most popular material since the 1990s is the 21st century materials. Some critics also said that the diamond film era has already dawned. According to statistics from the International Resource Development Corporation, diamond film products will go to market at almost twice the annual rate. Experts predict that the direct product of diamond film will exceed 10 billion US dollars from 2000 to 2010, which is equivalent to twice the market of synthetic diamond products. 5.6 Although CVD diamond and its products have entered the market, the scale is lower than expected. The main reasons are: (1) The cost of CVD diamond is still high, especially for high-end products, mainly for military and national defense, and the cost should be reduced. It is one of the important directions for future research; (2) Because CVD diamond products are new technology products, they still need to be recognized by relevant companies; (3) New products involve many fields of technology, and there are technical difficulties to be solved. References 1. Sun Shanxiang, CVD diamond film investment financial analysis [J]. Superhard Materials Engineering, 2007, 4:43~45 2. Song Jianmin, Diamond Cold Cathode [J]. Industrial Materials, 1998, 141, 115~123 3. Song Jianmin, Diamond Semiconductor [J] Industrial Materials, 1997, 138, 171 ~176 4. OJGuy, D.Doneddu, M.Loodzinski, P.lgic, R.Albery, et.al., Maximixing the performance of single-crystal diamond Schottky diodes and FETS[J].IDR,2007,3:65 ~67 5. B.Palethorpe, D.Trainer, High temperature power electronies for the More Electric Aireraft [J].IDR,2007,2:19~22 6. microwave devices.com. 7. J.Morse, M.Salome and R.Barrett, Single crystal CVD diamond for synchrotron X-ray beam monitoring[J].DIR,2006,3:34~40 8. detechtors.com 9. Elaine Maclarence, Optical applications of diamond- An overview of current applications[J].IDR,2007,3:41~43 10. BMvan Oerle, TJSchaich et.al.,High NA diamond lenses for near fiele optical data storge[J]IDR,2006,4:51~ 52,57 11. He Jinghui, Qin Songyan et al. Research progress in preparation of nano-diamond films by CVD method [C]. The 5th Zhengzhou Proceedings of the Symposium on Superhard Materials and Products, 2008, 9:123127 12. Liu Mai, Zhou Bing, et al. Research on CVD diamond film ultra-precision tool technology [J]. Superhard Materials Engineering, 2008, 2:38~41 13 Jiang Liuxiang, Application and Market Prospect of CVD Diamond Film, [M] Progress in Diamond Film Research, Beijing: Chemical Industry Press, 1991 14. Tang Cunyin, Diamond Film Traveling Space [J]. Superhard Materials Engineering, 2005, 1:45 15. Tang Cunyin, Diamond Film Applied to Nano-Calculator [J]. Superhard Materials Engineering, 2007, 4:55 16. Deng Hua, China's nano-diamond composite coating technology successfully realized industrialization [J]. Industrial Diamond, 2006 , 1:10 17. Wang Guangzu, Micron/nano-diamond film performance and application [J]. Jewelry Technology, 2004, 5:36~39 18. Wang Guangzu, all aspects of CVD diamond application [J]. Abrasives Newsletter, 2009 , 4:11~14
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