FZ silicon application

Not only impurities but also mechanical and morphologic material properties could be harmonized and enhanced to achieve product capable for FZ processing which is an ultimate requirement in polysilicon production.

The continuous efforts for optimization and development which we implement in our plant have led to the production of high quality polysilicon rods for the FZ processes. We identified the influencing variables and to control quality parameters during the production process to achieve target specification of the FZ rod.

Production of FZ silicon feedstock by the Siemens Process

  Control of FZ Quality impurities:  
Main challenges to produce FZ rods:

  • geometry, rod structure, surface morphology
    • FZ capability
  • low stress silicon
    • FZ capability
  • purity (dopants, metals, non-metals, particles)
    • FZ crystal yield
  • Ultra low level of dopants
  • Ultra low level of transition metals
  • Low level of Carbon content
  • No particles allowed
    • Control of metalls and non-metalls
    • Control of Si particle formation