Silicon – Not Just for Silicones

The element silicon, together with a wide range of its compounds that are not classified as silicones, are used in both traditional products (glassware, clays etc.) and in high-tech industry. Foremost among the latter are the computer-chip and photovoltaic industries. Silicon is also contained in various metal alloys. The following diagram illustrates the world consumption of silicon wafers (green) and market growth (red).




The fabrication of silicon wafers in the chip industry requires silicon that is almost 100 % pure. Special processes are used to seed raw silicon with a pure silicon crystal so that a solid silicon ingot (right in the picture) can be pulled. The requisite wafers are then sawn from the ingot. Each of these working stages requires cleanroom conditions, as even the tiniest dust particles would render the material unusable.	Polycrystalline silicon is also used in the field of photovoltaics. However, before light can be converted into electrical energy in photoelectric cells, the silicon has to be doped with foreign atoms. Given the search for alternative energy sources and hydrogen technology, this could well evolve into the principal application one day.	A so-called druse of silicon carbide is shown in the picture above. Due to its hardness and heat resistance, silicon carbide is widely used in the abrasive and ceramic industry.