Oxidation and diffusion

Which correctly compares dry oxidation (O2) and wet oxidation (H2O) in the thermal oxidation of silicon?

  1. ADry oxidation grows oxide faster
  2. BWet oxidation grows oxide faster
  3. CBoth grow oxide at the same rate
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Answer: B. Wet oxidation grows oxide faster

Wet oxidation with water vapor grows oxide much faster than dry oxidation because the oxidant is far more soluble in SiO2. It suits thick films such as those for device isolation. Dry oxidation is slower but produces dense, high-quality films, so it has been used for thin gate oxides.

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More Oxidation and diffusion questions

  1. When an SiO2 film of thickness x is formed by thermally oxidizing silicon, approximately how much silicon is consumed?
  2. How does the diffusion coefficient of dopants in silicon depend on temperature?
  3. Which method is mainly used for device isolation in scaled LSIs?
  4. Once the oxide has become sufficiently thick in thermal oxidation, how does its thickness relate to oxidation time?
  5. Why does oxide on silicon appear in different colors depending on its thickness?