Reinstsilizium

Reinstsilizium is ultra-high-purity silicon used in semiconductor fabrication and other high-precision applications. In German-language contexts, the term denotes silicon refined to extremely low impurity levels, suitable as a substrate or starting material for electronic-grade silicon and advanced research.

Purity levels for Reinstsilizium are commonly described as nine-nines (9N) or higher, corresponding to 99.9999999% silicon or more. Typical impurities include metallic contaminants such as iron, nickel, and chromium, as well as light elements like boron, phosphorus, oxygen, and carbon. Isotopically enriched variants, notably silicon-28, are used in specialized research and quantum applications.

Production involves purification of silicon from silica or chlorosilane precursors, followed by crystal growth. The Siemens process historically produces high-purity polycrystalline silicon, which can then be refined. For single-crystal ingots, the Czochralski (CZ) or float-zone (FZ) methods are commonly employed. Zone refining may further reduce residual impurities to achieve the highest-purity material required for demanding applications.

Properties of Reinstsilizium include high electrical resistivity and excellent semiconductor behavior, making it suitable for precise electronic control. The material is brittle and requires cleanroom handling and controlled processing to prevent contamination. Its melting point is about 1,414°C, and the room-temperature bandgap is 1.12 eV. Doping with p-type or n-type dopants enables tailored electrical properties for devices.

Applications are dominated by substrates for integrated circuits and power electronics, as well as photovoltaic cells and MEMS. It is also used in research platforms for quantum computing and photonics. The production and supply chain are concentrated among a few chemical and semiconductor companies, with stringent purity control and contamination prevention integral to quality.

Safety considerations include handling hazardous chemicals used in purification, such as chlorosilanes and fluorides, and the management of silicon dust, which can pose health risks. Appropriate protective equipment and waste management practices are required.