Silicon wafers

Which method has been used to make multicrystalline silicon ingots for solar cells cheaply and in large volumes?

  1. ACasting, in which the melt is solidified directionally in a mold
  2. BThe FZ method
  3. CMBE
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Answer: A. Casting, in which the melt is solidified directionally in a mold

In casting (directional solidification), molten silicon is solidified gradually from the bottom in a square mold to make a large multicrystalline ingot. Its quality is lower than single crystal, but it can be mass-produced cheaply, so it has been widely used for solar cells. Recently the share of single-crystal solar cells has grown.

  • A. Correct. The melt is solidified directionally in a mold.
  • B. The FZ method makes high-purity single crystals.
  • C. MBE grows thin films epitaxially.
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More Silicon wafers questions

  1. When finishing a CZ pull, why is the ingot diameter gradually reduced (a tail cone is formed) before separating it from the melt?
  2. Which is closest to the typical concentration of interstitial oxygen in silicon crystals grown by the CZ method?
  3. In the mirror polishing (final CMP polishing) of silicon wafers, what is commonly used as the abrasive in the slurry?
  4. What is the main use of low-resistivity n⁺ silicon wafers heavily doped with arsenic or antimony?
  5. When CZ silicon is heat-treated around 450 °C, oxygen atoms can cluster and act as donors, changing the wafer's resistivity. What is this called?