Method of purification of argon gas

I. Overview 

Argon gas is a protective gas for the production of monocrystalline and polycrystalline silicon. In order to improve the quality of silicon crystals, how to select higher purity argon gas is an issue in the production of silicon crystal. Through the use of this device, when the purity of argon is less than 1 ppm of oxygen and moisture is less than one ppm, the oxygen carbon content of monocrystalline silicon is less than 0.5 ppm, which improves the service life of monocrystals and meets the requirements, winning customer satisfaction and market demand. Since liquid argon is not purified after vaporization, its oxygen content is generally 2 ppm to 5 ppm. Sometimes the gas supplier provides argon beyond this range, and customers who use argon do not know its quality, so it often affects the quality of the produced product. After the existence of an argon purification device, regardless of the quality of the raw argon gas, the purity of the argon gas entering the crystallization furnace is always constant as long as it is treated by the purification device. Generally, the oxygen content is less than 0.5 ppm, and the water content is less than 1 ppm, so that the stable argon gas is guaranteed to produce the quality of the crystal. High purification system of argon

II. A method for the purification of argon

 A direct deoxygenation method. It is to use the active metal to react with the oxygen in argon, digest the oxygen from argon, and achieve the purpose of deoxygenation, through molecular sifting to absorb the water in argon so that the moisture content of argon is less than 1 ppm. The second is to use aerosols. At a certain temperature, the aerosol absorbs gases such as nitrogen, hydrogen, oxygen, carbon monoxide, carbon dioxide, and methane. After the absorption treatment, the purity of argon can reach 6 niths, and this protective gas is more suitable for monocrystalline silicon for the production of high purity semiconductors. Purity of argon after purification with getter: O2 ≤ 0.2ppm H2 ≤ 0.5ppm N2 ≤ 1ppm CO + CO2 ≤ 0.5ppm CH4 ≤ 0.5ppm Water ≤ 1ppm A method of equipment investment is small, the service life of the deoxidizer in the equipment is generally greater than four years. The second method has a high purity of equipment but a relatively large investment, and the aerosol has a service life of two years. The purity of gas in equipment can also be tested on an on-line basis with an analyzer according to customer requirements.

III. Use of argon 

High-purity argon is used in welding, stainless steel manufacturing, In smelting, argon is also used in semiconductor manufacturing processes for chemical gas precipitation, crystal growth, heat oxidation, extension, diffusion, polycrystalline silicon, tungstenization, ion injection, loading, sintering, etc. as the protective gas for the production of monocrystalline and polycrystalline silica.