Applications of Silane
Aug. 22, 2020
Silane refers to the silicon-substituted analog of carbon alkanes. What constitutes silane hydrocarbons is a main chain formed by linking silicon atoms and hydrogen atoms linked to the main chain by covalent bonds. The general formula of silane hydrocarbon is SinH2n+2.
In 1857, the German chemist H Buff discovered silane. In the next 100 years or so, silane was only the object of a few researchers in the laboratory and had no purpose. With the rise of semiconductor technology in the 1950s, people began to consider the advantages of silane, and silane began to be used in the electronics industry. In the 1980s, the application of silane has undergone major changes. With the emergence of a series of new technologies or the success of using silane to develop new products, the amount of silane has increased dramatically. Thousands of tons of silane are processed into ultra-pure semiconductor silicon in factories every year, and hundreds of tons of gas are used to manufacture a variety of new materials and new devices. Considering that in these applications, most devices consume only milligrams or even micrograms of gas, and the thickness of the film made of silane is on the order of microns. It can be seen that the amount of silane is not a small number. In the 1990s, a larger number of new functional devices came out, including ultra-high-speed, ultra-large-capacity computer chips, high-resolution flat-panel displays, high-efficiency and low-cost solar cells, high-performance ceramic engine parts, and various special functions that have been developed on a large scale. More newer devices are still emerging, and these devices all use silane.
The reason why silane is widely used in high technology and becoming more and more important is firstly related to its characteristics, but also related to the special needs of modern high technology. Through thermal decomposition or chemical reaction with other gases, a series of silicon-containing substances such as monocrystalline silicon, polycrystalline silicon, amorphous silicon, metal silicide, silicon nitride, silicon carbide, and silicon oxide can be prepared from silane. The use of silane can achieve the highest purity, the finest (up to atomic size) control and the most flexible chemical reactions. Therefore, various silicon-containing materials can be made into complex and fine structures according to various needs, which is the basic condition required by modern materials and devices with various special functions.
Silane was first put into practical use and used most widely as an intermediate product for the production of high-purity silicon, generally called the silane method. The main method for producing high-purity silicon has been the trichlorosilane method (Siemens method).
Another application of silane is amorphous semiconductor amorphous silicon. Compared with single crystal semiconductor materials, amorphous silicon is characterized by being easy to form very thin (about 10nm thick) large area devices. The substrate can be glass, stainless steel, or even plastic, and the surface can be flat or curved, so it can be made Various devices with excellent performance.
Silane has become the most important special gas used in semiconductor microelectronics processes and is used in the preparation of various microelectronic films, including single crystal films, microcrystalline, polycrystalline, silicon oxide, silicon nitride, and metal silicides. The microelectronic applications of silane are still developing in depth: low-temperature epitaxy, selective epitaxy, heteroepitaxial growth. Not only for silicon devices and silicon integrated circuits, but also for compound semiconductor devices (gallium arsenide, silicon carbide, etc.). It also has applications in the preparation of superlattice quantum well materials. It can be said that silane is used in almost all advanced integrated circuit production lines in modern times. The purity of silane has a great influence on device performance and yield, and more advanced devices require higher purity silane (including disilane and trisilane).
The application of silane chemistry as silicon-containing films and coatings has expanded from the traditional microelectronics industry to various fields such as steel, machinery, chemicals, and optics. The silicon-containing coating can increase the high-temperature oxidation resistance of ordinary steel to more than 100,000 times, and can also greatly improve the high-temperature chemical stability of other metals, so that the corrosion resistance of internal combustion engine blades is significantly enhanced, and various materials and parts The bonding strength between the two is greatly improved, which extends the life of automobile engine parts, and can also change the reflection and transmission properties of the glass, thereby obtaining significant energy saving and decorative effects. In the float glass production process, silane is used to coat a reflective layer on the glass surface. Its adhesion is extremely strong and will not fade under long-term sunlight. The light transmittance is only 1 /3 of ordinary glass; it is coated with silicon nitride The large area polycrystalline silicon cell (BSNSC) has reached a high efficiency of 15.7%. The use of silane vapor deposition technology to manufacture various silicon-containing films in high-tech applications is still increasing.
Another potential application of silane is the manufacture of high-performance ceramic engine parts, especially the use of silane to make silicide (Si3N4, SiC, etc.) micropowder technology has attracted more and more attention. The United States, Japan and other countries are spending hundreds of millions of dollars to develop high-temperature resistant, high-strength, and high-chemically stable ceramics from silicon, silicon nitride and silicon carbide micropowders. The micropowder prepared by the silane gas phase reaction method has the highest purity, fine and uniform particle size, which can greatly improve the performance of ceramic parts. It has a wide range of applications, such as automotive engine valves and turbocharger rotors have been practical, high-speed bearings and high-performance tools have been commercialized, used in internal combustion engines can make the operating temperature up to 1400 ℃, greatly improve the efficiency of the heat engine, and it is more suitable This kind of fuel can extend the service life; in addition, it can also be used as the insulation tile and stealth protection layer of the rocket.