The Nine-Nines Problem

10 atomic recall cards. Export to Anki and let spaced repetition do its slow work.

In Anki: File → Import, choose this TSV, set field separator to Tab, deck = Sand to Silicon · Ch 03, note type = Basic.

Front	Back
What chemical is produced when MG-Si reacts with hydrogen chloride?	Trichlorosilane (SiHCl₃).
What is the boiling point of trichlorosilane?	31.8°C.
What is the boiling point of boron trichloride (BCl₃), and why does it matter?	12.6°C — different from trichlorosilane’s 31.8°C, so the two separate cleanly in a fractional distillation column.
What fraction of remaining impurities does each pass through a distillation column remove?	90% or more per pass.
At what temperature are Siemens reactor seed rods held during deposition?	About 1,100°C.
What purity designation (N-grade) is sufficient for solar panels?	6N — 99.9999%.
What purity grade is the floor for memory chips?	9N — 99.9999999%.
What purity range does leading-edge logic demand, per the chapter?	10N to 11N.
What is the main energy disadvantage of the Siemens process?	Most of the energy — in the 90–170 kWh/kg range for electronic grade — is lost as heat radiated from the incandescent rods.
How does the FBR process differ from Siemens in its product form and energy use?	FBR uses silane gas (SiH₄) and produces polysilicon as small beads instead of rods, at roughly one-fifth the energy cost of Siemens.