Meaning
Czochralski grown monocrystalline silicon with reduced levels of interstitial oxygen atoms provides a stable substrate for high performance power electronics and radio frequency devices. Production of low oxygen cz silicon requires specialized crucibles or magnetic fields to limit the erosion of the quartz container during the melting process. Lowering the oxygen content minimizes the formation of unwanted precipitates that can degrade electrical performance.
This material is preferred for applications where high resistivity must be maintained through multiple high temperature fabrication cycles.
Crystal Growth
Control over the rotation of the melt and the application of magnetic forces reduces the incorporation of oxygen from the silica walls. In standard processes, oxygen is a common impurity that migrates from the crucible into the silicon lattice. Manufacturers of low oxygen cz silicon use these advanced techniques to keep concentrations below specific parts per million thresholds.
Defect Prevention
Minimizing oxygen levels prevents the creation of thermal donors that would otherwise alter the resistivity of the wafer during subsequent heating cycles. In power amplifier applications, low oxygen cz silicon ensures that the parasitic capacitance remains low and predictable. The resulting wafers exhibit fewer structural flaws which improves the yield of the fabrication process.
Thermal Process
Stability during high temperature annealing or oxidation steps is a primary benefit of using this specific grade of material. Engineers specify low oxygen cz silicon for devices that must undergo multiple fabrication steps without losing their intended electrical characteristics. Consistent performance across the wafer surface reduces the need for individual component binning.
