Blocks from semiconductor material are called ingots. Monocrystalline silicon ingots (monocrystals) are produced from ultrapure silicon using the so-called Czochralski process: a cylindrical monocrystalline ingot is initialized with a small seed crystal and then pulled from a crucible with molten silicon. Multicrystalline siocon ingots (multicrystals) aer produced from pure silicon in a process with a duration of approx. 50 hours (heating and melting followed by gradual cooling and controlled solidification). During this process, the mm- to cm-sized crystalline grains form in the ingot.