Float Zone Wafers (FZ)

SVM Float Zone Wafer Sample Specifications:

• FZ silicon wafer
• Diameter:  50mm, 76mm, 100mm, 125mm, 150mm, 200mm
• Type/Dopant: N/Phosphorus, P/Boron, Intrinsic
• Orientation: <100>, <110>, <111>
• Resistivity: <5 ohm-cm to >10,000 ohm-cm – SVM can supply numerous resistivity ranges for FZ wafers, contact SVM to see if we have your specification available.
• Thickness: SEMI standard thicknesses available at each diameter, custom thicknesses available upon request.
• Flats: 1 / SEMI standard – depending on SEMI standard for given diameter.
• TTV: < 5μm
• Front side: Polished
• Back side: Etched or polished – both available, depending on other project specifications.

Float Zone Wafer Fabrication

Float zone wafers (FZ) are an alternative to czochralski (CZ) wafers and are high in purity. These wafers have a low concentration of impurities and high temperature capabilities. The properties of FZ wafers give them advantages over CZ wafers in a variety of applications. The FZ growth process begins with a silicon ingot that slowly rotates and passes through a heating element. A portion of the ingot is partially melted as the heating element moves along the ingot. As the silicon re-solidifies, the imperfections remain in the melted portion as the heating element continues to rotate and move along the ingot. After the entire ingot passes through the heating element and dopants are added, it is cooled and sliced. The entire growth process takes place either in a vacuum, or in an environment that contains only inert gasses, allowing for the ingot to grow in an environment with very minimal contamination.

The ingot may be doped positively (P-type), negatively (N-type), or not at all (intrinsic) during the growth process, depending on the end user’s application. The high purity of FZ ingot means the silicon has minimal carbon and oxygen contamination, as well as minimal amounts of nitrogen in order to control microdefects within the ingot. Their properties allow for a more efficient doping process, which sometimes produces resistivity measurements reaching up to 50,000 ohm-cm.

Float zone wafers are commonly used in the manufacturing of discrete power devices, high efficiency solar cells, radio frequency (RF) chips and optical products. These wafers are also prevalent in high temperature applications because elements like oxygen and carbon are less likely to become active and damage the wafer at higher temperatures.

Silicon Valley Microelectronics offers FZ wafers ranging in diameter from 50mm to 200mm. Intrinsic wafers are also available upon request.