Silicon wafers

Which is closest to the typical concentration of interstitial oxygen in silicon crystals grown by the CZ method?

  1. AAbout 10¹⁸ cm⁻³
  2. BAbout 10²³ cm⁻³
  3. CAbout 10¹⁰ cm⁻³
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Answer: A. About 10¹⁸ cm⁻³

CZ crystals contain oxygen dissolved from the quartz crucible at roughly 10¹⁷ to 10¹⁸ cm⁻³ (a few to over ten ppma). This oxygen precipitates during heat treatment and helps with gettering, but too much causes defects, so its concentration is controlled.

  • A. Correct. About 10¹⁷ to 10¹⁸ cm⁻³ is typical.
  • B. About 10²³ cm⁻³ exceeds silicon's atomic density (about 5×10²² cm⁻³), which is impossible.
  • C. About 10¹⁰ cm⁻³ is on the order of the intrinsic carrier density, far too low for oxygen.
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More Silicon wafers questions

  1. In the mirror polishing (final CMP polishing) of silicon wafers, what is commonly used as the abrasive in the slurry?
  2. What is the main use of low-resistivity n⁺ silicon wafers heavily doped with arsenic or antimony?
  3. 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?
  4. To analyze metal contamination on a wafer surface with high sensitivity, which preparation method dissolves the surface oxide with hydrofluoric acid vapor and collects it in a droplet for analysis?
  5. What are the very gentle undulations on a wafer surface, with lateral wavelengths of a few millimeters and heights of tens of nanometers, called?