Oxidation and diffusion

When thin oxides of a few tens of nanometers or less are grown by dry oxidation, which known deviation from the Deal-Grove model occurs?

  1. AInitial oxidation proceeds faster than the model predicts
  2. BOxidation does not proceed at all
  3. CThe oxide becomes a conductor
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Answer: A. Initial oxidation proceeds faster than the model predicts

The Deal-Grove model describes thick oxide growth well, but in the initial regime of dry oxidation below a few tens of nanometers, actual oxidation proceeds faster than the model predicts. Predicting the thickness of thin gate oxides therefore requires models that account for this initial enhancement, or measurements.

  • A. Correct. Oxidation is faster than the model in the initial thin regime.
  • B. Oxidation does proceed.
  • C. SiO2 is an insulator and does not become a conductor.
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More Oxidation and diffusion questions

  1. In LOCOS, what is the phenomenon called in which a thin nitride forms on the silicon surface under the nitride mask, later causing the gate oxide there to be locally thin or defective?
  2. Why does the compressive stress in thermally grown oxide become smaller when oxidation is done above about 950 °C?
  3. Why can SiO2 serve as a diffusion mask against boron and phosphorus but works poorly as a mask against gallium and aluminum?
  4. In regions where the impurity concentration far exceeds the intrinsic carrier density, the diffusion coefficient of arsenic and others varies with concentration. Which statement about this is correct?
  5. Which correctly describes the thermal oxidation of heavily doped polycrystalline silicon (polysilicon)?