Floatzone
Float-zone, or floating-zone, is a crucible-free method for growing high-purity single crystals of semiconductors. In this process, a narrow molten zone is created in a polycrystalline rod and is moved along the length of the material. As the molten zone passes, the material behind it recrystallizes as a single crystal, while impurities are rejected and carried ahead into the remaining feed material. This technique is especially valued for producing ultra-pure silicon and germanium, and it is also used for certain compound semiconductors. The absence of a container reduces contamination from crucible materials, contributing to lower impurity levels and higher crystal quality.
Principle and operation: The localized heating can be produced by induction or radiant heating. The molten
Equipment and materials: Float-zone systems include a feed rod, a seed or oriented crystal, a precise heater,
Applications and limitations: The technique is widely used to prepare high-purity silicon wafers for electronics and