Float-Zone process

In a chamber, a purified, polycrystalline silicon rod (source rod) is positioned above a high-frequency induction coil. To avoid electrical breakdown, the process is usually conducted in an argon atmosphere at pressures between 0.5 and 5 bar. By adding suitable gases, such as phosphine or diborane, which diffuse into the melt, enables doping of the silicon.
By coupling the high frequency  into the silicon rod near the surface, the lower end is melted contactlessly. To ensure the zone melts as homogeneously as possible, the rod is slowly rotated.

The molten zone is brought into contact with a thin monocrystalline seed crystal located below the coil and moved upward through a small hole in the center of the coil. After the seed crystal is brought into contact with the liquid lower end of the source rod, the seed crystal  is slowly moved downward and also rotated. A monocrystalline crystal then grows according to the crystal structure and orientation of the seed. The liquid zone is maintained by slowly feeding and melting the source rod from above while the monocrystal continues to grow at the bottom of the seed crystal.

The floating-zone (FZ) technology enables the production of ultra-pure silicon monocrystals with high resistivity for high-performance electronics and semiconductor applications. Thanks to continuous gas-phase doping, a homogeneous resistivity distribution can be achieved over the entire crystal length, ensuring the desired electrical properties are uniformly present in the crystal.

Compared to the Czochralski process, the Float-Zone process offers lower material and energy costs, as no costly quartz crucibles are required and only a small crystal section is heated. The pulling speed is significantly higher. Additionally, repeated processing can gradually improve the purity of the silicon crystals.

For the production of standard and customer‑specific pressure vessels, components, and vacuum chambers, we operate our own manufacturing facility in Europe. It is entirely powered without the use of fossil fuels, fully aligning with our sustainability objectives.

Key advantages at a glance

• Fast delivery times: Greater independence from external suppliers
• Flexible customization: Short‑notice design changes can be implemented immediately.
• Reliable material availability: Constant access to high‑quality materials thanks to long‑standing local partnerships.
• Highest processing quality incl. standards: Performing welding operations in‑house allows direct monitoring of joint conformity, which is essential for meeting standards such as UNI EN ISO 3834.
• Top‑tier standards: Naturally, our facility meets our stringent requirements for quality, safety, and sustainability.