Czochralskimetoden

The Czochralski method, also known as crystal pulling, is a widely used industrial process for the purification of silicon and the growth of single crystals of semiconductors, metals, and salts. Developed by Polish scientist Jan Czochralski in 1918, it involves melting a polycrystalline material in a crucible, typically made of quartz. A seed crystal, which is a small, perfectly formed single crystal of the desired material, is then lowered to touch the surface of the molten material. The seed crystal is slowly rotated and withdrawn from the melt. As it is pulled upwards, the molten material solidifies onto the seed crystal, replicating its crystal structure. The rate of pulling and the temperature gradient are carefully controlled to ensure that the solidification occurs in a controlled manner, resulting in a large, single crystal ingot. The process is commonly used to produce the cylindrical ingots of ultrapure silicon that form the basis of the semiconductor industry, where they are subsequently sliced into wafers for microchip fabrication. Other materials, such as sapphire, gallium arsenide, and various oxides, can also be grown using this technique.