Silicon from sand is a promising technology for producing silicon of semiconductor quality

Abstract

An analysis of the methods for obtaining silicon of semiconductor quality determined the relevance of the issues of compliance of modern technologies with environmental requirements of today, as well as the possibilities of raw materials and energy supply for a potential increase in production volumes. The development of production requires a search for compromises between the needs of society and the consequences expressed in the environmental impact on nature, the growth in the consumption of raw materials and energy. The proposal to use quartz sand instead of quartzite is promising due to the solution of the problems of raw material supply for the production of silicon of semiconductor quality for many years to come. The technology of chlorination of quartz sands proposed for implementation has been tested in industrial conditions and, in addition to the problems of raw material supply, to a large extent solves the problems of environmental and energy supply.Within the framework of the set environmental task, the problems of decarbonization of production are first of all solved by eliminating the energy-consuming high-temperature process of carbothermal reduction of silicon. The proposed technological solution provides a compromise between environmental friendliness and energy efficiency by involving silicon-containing materials, technogenic wastes, as “energy donors” in physical and chemical processes. Chlorination of the prepared raw materials is carried out in the solid phase, which is an energy-efficient solution, as it eliminates the cost of energy to compensate for the latent energy of melting. The initial preparation of raw materials involves the procedure of mechanoactivation - energy-efficient activation of the raw material by destroying intercrystalline bonds. The use of “energy donors” in blending ensures that the chlorination process is carried out in the autothermal mode, reducing the specific consumption of chlorine for the process. The problems of high energy intensity in the production of silicon of semiconductor quality are also solved by adjusting the technological scheme with the exclusion of energy-consuming low-temperature processes.The implementation of the proposed technological solutions is focused on the maximum use of known technological equipment, which minimizes the costs of design and production development of the technology. Based on the practical data obtained, system solutions for integrating the new technology into the schemes of existing enterprises are proposed - providing variability of adaptation in terms of raw material supply and the range of produced polycrystalline silicon of both “electronic” and “solar” quality. Based on the practical data obtained, system solutions were proposed for integrating the new technology into the schemes of existing enterprises - providing variability of adaptation in terms of raw material supply and the range of produced polycrystalline silicon of both “electronic” and “solar” quality.