Czochralski Process (Cz)
The Czochralski process (Cz) is also known as “crystal pulling” or “pulling from the melt”. In this process, Silicon (Si) is first melted and then allowed to freeze into a crystalline state in a controlled manner. The advantage of this method is that it is fast and highly controllable. The industrial cultivation of high-purity monocrystalline Silicon crystals using the Cz Process has become well established primarily for the solar and semiconductor industries (in the computer industry for integrated circuits and in microsystem technology). You benefit from the high effectiveness and quality of the cultivated crystals.
The Process
To begin with, high-purity polycrystalline silicon is placed in the Silica crucible of a single crystal pulling system and then melted in a controlled atmosphere (Argon) using a resistance heater. Once the temperature of the melt has stabilized (the melting point is around 1,412 °C), a rotating monocrystalline Silicon seed crystal is dipped into the melt. A slight temperature drop initiates the crystallization of Silicon on the seed crystal. When the seed crystal is slowly pulled upward, a cylindrical Silicon monocrystal hanging on the seed crystal starts to form. The pulling rate and temperature are regulated such that a Silicon monocrystal—whose orientation and structure is identical to those of the seed crystal—can be pulled with a constant diameter.
Applications
Our EKZ-series systems are specially designed for the Cz process and enable the production of high-performance Silicon monocrystals.