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Preparation and application of titanium nitride thin films

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Update time : 2020-05-25 14:27:40
1. Preparation method of TiN films
The research on TiN thin films started as early as the 1960s, but the difficulties in the preparation of materials and devices led to a low tide of research work. Later, with the improvement of film preparation technology, the research on TiN films began to be active at home and abroad, and the preparation methods were also diversified. At present, great progress has been made. The preparation methods of TiN films can be divided into physical vapor deposition and chemical vapor deposition.
1.1 physical vapor deposition (PVD)
1.1.1 electron beam evaporation
TiN thin films prepared by vacuum coating method are rarely used at home and abroad, mainly because of its poor combination with substrate and poor process repeatability. At present, electron beam evaporation is the most widely used vacuum coating method at home and abroad. It is a method of using an electron beam to hit the surface of a material to be vaporized to transfer energy to the material to be vaporized so that it melts and evaporates. It has the characteristics of high energy density, high thermal efficiency, less loss of thermal conduction and radiation, etc., which can reduce the reaction between the container material and the plating material. The purity of TiN coating can be greatly improved.
                                                
1.1.2 sputtering coating method
There are two main techniques for preparing TiN thin films by magnetron sputtering: dc magnetron sputtering and rf magnetron sputtering (using ceramic TiN targets). Recently, non-equilibrium magnetron sputtering and reactive sputtering have appeared. The reactive sputtering method was first used in the preparation of TiN films due to its unique advantages. In addition, the non-equilibrium magnetron sputtering method is also a common sputtering method at home and abroad. The preparation of TiN films by magnetron sputtering has the advantages of high sputtering rate, low substrate temperature rise, good membrane base adhesion, stable device performance and easy operation and control. At the same time, it also has some disadvantages, such as its lower deposition rate and lower efficiency, which is unfavorable for reducing deposition cost. Therefore, the magnetron sputtering method is only applied in the fields requiring higher TiN coating, such as optics and microelectronics.
1.1.3 arc ion plating
Since the 1980s, the preparation of TiN coating by ion plating has become a new and high technology in the world, mainly used in the preparation of high speed steel and cemented carbide tools or related systems of wear resistant coating and stainless steel products on the imitation of gold decorative coating. In the 1990s, the technology of ion plating has made great progress. At present, the most widely used technology of ion plating is arc ion plating (also known as multi-arc ion plating), which has replaced other types of ion plating and become the only production process of titanium nitride coating industry. During the deposition of TiN coating by arc ion plating, the factors affecting the structure and performance of the coating are arc current, substrate negative bias pressure, substrate temperature, partial pressure of nitrogen, cavity pressure, etc.
1.1.4 plasma immersion ion implantation technology
The method of preparing TiN films by plasma immersion ion implantation (PIII) was first invented by professor Conrad, who found that PIII technology can simultaneously inject and process a batch of workpiece. Therefore, the process and equipment of this method are very simple, which can greatly reduce the production cost and has a good application value in the preparation of TiN films. Plasma immersion ion injection /k is a deposition method in which the injected elements in the plasma are vertically injected into all surfaces in an omni-directional manner under the action of strong electric field forces during the PIII process.
1.2 chemical vapor deposition (CVD)
1.2.1 general chemical vapor deposition (CVD) method
CVD method is a new technology for preparing inorganic materials developed in the 1960s, and the technology for preparing TiN films by CVD method is very mature abroad. As early as the late 1960s, a Swedish company, Sandwick, used CVD technology to deposit TiN coatings on cemented carbide tools. The technology was quickly commercialized because of the lower cost of CVD technology and the significantly longer tool life that TiN coatings provided. Compared with PVD method, chemical vapor deposition of N coating is characterized by fast film forming speed, good diffraction property of coating film, high purity of coating, complete crystallization, smooth deposition surface and low radiation damage. However, due to the need of high temperature, high vacuum and other environmental conditions, the application of the device has been greatly limited.
1.2.2 plasma enhanced chemical vapor deposition
Since the 1990s, the pulsed dc PCVD coating technology has made great progress in the preparation of Ti, which can significantly improve the microstructure and performance of the coating, and has been preliminarily used in various industrial tools and molds, with definite results. At present, the PCVD coating method is developing very fast at home and abroad. The plasma chemical vapor deposition method not only has the good wrapping property of CVD. Moreover, it has fewer pinholes, densification, less internal stress and less microcrack than that obtained by CVD method. At present, there are three kinds of PCVD power supply: dc, rf and microwave.
1.2.3 laser chemical vapor deposition
The preparation of TiN thin films by laser chemical vapor deposition (LCVD) is a very attractive method. The most important thing is that it can be used to obtain high quality TiN films without damage. At present, the TiN films prepared by this technique have a very broad application prospect, and the technology of preparing TiN ceramic films by LCVD has developed rapidly in the recent stage. Laser chemical vapor deposition (LCVD) is a chemical vapor deposition method of thin films using laser beam. It makes full use of laser's high energy density and fast heating speed, and the deposition speed is greatly accelerated. Compared with common CVD, it has the advantages of low temperature, low damage, fine processing and selective growth. At present, the domestic technology of laser chemical vapor deposition has reached the international advanced level.
                                                      
2. Application of TiN films
2.1 mechanical processing industry
TiN film can reduce the adhesion of cutting edge materials, improve cutting force, improve the surface quality of the workpiece, and multiply the service life and durability of cutting tools. Therefore, TiN films are widely used in the coating of low-speed cutting tools, high-speed steel cutting, wood cutting tools and drill bits. In addition, the TiN is worn parts of ideal wear-resistant coating, especially because of its low gelling tend to widen the application of wear in many systems, such as automobile engine piston sealing ring, all kinds of bearings and gears, such as: in addition, TiN are also widely used in the molding tool coating technology, such as sheet molding tool coatings in automotive industry.
2.2 medical industry
TiN film is non-toxic, light weight, high strength and has excellent biocompatibility, so it is an ideal medical metal material, which can be used as implants and surgical instruments for human implantation. In addition, titanium nitride films can be used as other excellent biocompatibility films. The mechanical properties and adhesion of hydroxyapatite film (HA), a commonly used medical material, were greatly improved by Nelea et al.
2.3 aerospace
Coat IF - MS2 with TiN film. The wear resistance of sulfur dimolybdate lubricant can be improved. TIN film is coated on if-ms2. Because of its characteristics of high hardness, high melting point, high wear resistance and excellent chemical stability, it can not only improve the lubrication performance of aircraft and spacecraft engines and other parts, but also ensure the high temperature and friction resistance of aerospace parts.
2.4 application of solar energy
The research of TiN thin films for stabilizing solar absorbing layer in high temperature atmosphere began in 1984. Recently (Ti, A1)N coating has also been recommended for solar selective absorbing layer and solar control window, mainly because of the high temperature resistance of (Ti, AI)N coating. Application of TiN and TiA1N coatings in solar energy field. It is still being tried and explored.
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