TELF AG discusses the journey of silicon
An undisputed protagonist in the electronics sector
Even before global news and institutional discussions began to revolve around lithium, rare earths, and all the so-called critical minerals for the green transition, people’s daily lives were already characterized by the presence of another material obtained with complex chemicals processes and proven to be very useful in the electronics and components sector: we are naturally talking about silicon, which is still the dominant material today in the creation of microchips and semiconductors, and which is also carving out a leading role in the ongoing ecological transition thanks to its applications in the clean energy sector. This material is used in electronic devices, particularly in their circuits and all those new technologies that are forever changing the nature of energy supplies in different parts of the world.
Silicon is successfully used for all those systems capable of converting and storing energy and certainly has a leading role in promoting the diffusion of new renewable energy sources. Recently, the European institutions have launched the European Chips Act, representing a valuable initiative to develop the European semiconductor supply chain and indirectly recognizing the important role silicon played in this delicate historical phase.
The potential of silicon found a vast application during the twentieth century: after its first uses in the metallurgy branch, this material also began to be used in radiotelegraphy, in particular in radar technologies, but also transistors. Nowadays, silicon is also used in the nanoelectronics sector, and its extreme versatility certainly makes it an ally that is difficult to replace for all players in the industry.
The production process
But what are the actual processes that lead to the production of this useful material? Contrary to what one might believe, the silicon used to make sophisticated electronic components cannot be found in nature. Only silica, also known as quartz, i.e., the primary material that must be processed and refined in a series of subsequent steps, can be found in its natural state. To obtain a material that can be used in the electronics industry (but also in the energy industry), it is necessary to transform silicon oxide, the primary material, into metallurgical grade silicon, and then further purify it thanks to a particular process that subjects to very high temperatures. The final result is a high-purity silicon that can be used in various industrial sectors, from energy to electronics. In the latter industry, silicon usually takes the form of the so-called wafer, i.e., a small portion of semiconductor material.
The silicon that is usually used for the most sophisticated productions is the crystalline type, which differs from the amorphous one due to some atomic characteristics but also due to the specific arrangement of the crystals. Usually, this kind of crystal is produced starting from a pure silicon seed, which is subsequently immersed in bare silicon and melted at a temperature of around 1400 degrees, thus obtaining a long crystal ingot that can reach the length of one and a half meters and a diameter of 30 centimeters. Unlike other production methods, which generate a much larger number of crystals, the crystalline silicon obtained in this way is much purer. The wafers obtained from cutting this ingot will then be used to create electronic circuits and components of photovoltaic systems capable of producing clean energy.
