Refining of silicon by the Czochralski technology is the most common method of producing monocrystalline silicon. Large diameter monocrystalline silicon can be grown with the Czochralski technique. As is the case for Float Zone technology growth of Czochralski monocrystalline silicon starts from a small diameter monocrystalline seed crystal. Czochralski silicon is pulled from a crucible in which the silicon is kept in the molten phase by heating the rotating crucible either by induction or resistive heating. Segregation of impurities between the liquid phase and the soild phase is as good as is the case for Float Zone silicon, but care must be taken during Czochralski growth in order not to contaminate the molten silicon from the surrounding atmosphere. Because of the open furnace principle it is difficult to grow Czochralski silicon with resistivities above 1.000 Wcm. Czochralski silicon is mainly grown with resistivities below 100 Wcm which is sufficient for the making of most IC´s, including low- to medium power IC´s.

In comparison with Float Zone silicon, Czochralski silicon can be grown to very low resistivities in the order of 1-2 mWcm. This is important for low and medium power applications, where the Czochralski silicon wafer serves as a carrier substrate for the actual components that is build on epitaxial material deposited on top of the Czochralski silicon wafer. When growing to these very low resistivities it becomes important to control the oxygen content in the silicon, and, big efforts are being invested into oxygen control issues. Also, issues concering resistivity control becomes important at these low resistivities. This is both axial control issues and radial resistivity gradient control issues.

Topsil has more than 40 years of experience in different silicon growth technologies including Czochralski technology. Topsil is offering a broad range of Czochralski products for applications within Power electronics, IC manufacturing and MEMS.