FZ Wafers | The Float Zone and Czochralski Crystal Growth Processes


July 22, 2019

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High-quality integrated circuits are built on highly pure single-crystal silicon, which is grown through the Float Zone or the Czochralski method. Both methods have their unique processes to produce effective and efficient wafers or FZ wafers for various electronic applications. To help you understand the difference between the methods, here is the Float Zone and Czochralski Crystal Growth Processes.

Czochralski Crystal Growth Method

The CZ or Czochralski method is a crystal-growing process that has something to do with the crystalline solidification of atoms from a fluid phase at an interface.Steps:

  • A charge of undoped EGS combined with an accurate amount of thinned silicon alloy is fused with a silica crucible.
  • Then, the gases present inside the growth chamber are cleared out.
  • It will then be back-filled with inert gas to prevent atmospheric gases from penetrating the melt during the crystal growth process.
  • At a temperature of 1421 degrees Celsius, the Si charge will then be melted inside the chamber.
  • A slender seed of crystal silicon with an accurate orientation resistance is then added into the molten silicon.
  • And finally, while the seed crystal and the crucible are rotated in opposite directions, the seed crystal is extracted at a controlled rate.

Float Zone Crystal Growth Method

The FZ or float zone method is another way of growing crystals to produce FZ wafers. It has something to do with the passing of a molten zone through a polysilicon rod. FZ wafers are often employed by those who require ultrapure silicon substrates.


  • Inside a chamber filled with an inert gas, a polysilicon rod is mounted vertically.
  • To create a molten zone, a needle-eye coil is stimulated to give RF power to the rod. This will melt the 2 cm long zone in the rod.
  • The coil is then put in motion, and the molten zone proceeds along with it.
  • As the molten zone moves along the entire length of the rod, it purifies the rod and creates a perfect single-crystal.
what are fz wafers?

Looking for FZ Wafers?

The Float zone method is a more employed method for those who seek ultrapure silicon substrates or FZ wafers. At Wafer World, we can provide you with high-quality FZ wafers according to your specifications. Call us for inquiries or purchase wafers online.

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