Oxidation and diffusion

Which compound has been used as a liquid diffusion source for introducing phosphorus into silicon by thermal diffusion?

  1. AArsine (AsH3)
  2. BPhosphorus oxychloride (POCl3)
  3. CDiborane (B2H6)
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Answer: B. Phosphorus oxychloride (POCl3)

Phosphorus oxychloride (POCl3) is vaporized by bubbling nitrogen through it and fed into the furnace with oxygen, forming a phosphorus-containing glass layer on the silicon surface from which phosphorus diffuses. It is still used, for example, to form the n-type layer of solar cells.

  • A. Arsine is an arsenic-containing gas.
  • B. Correct. It is a liquid phosphorus diffusion source.
  • C. Diborane is a boron-containing gas.
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More Oxidation and diffusion questions

  1. Which set represents the commonly used classification of charges in and at the interface of the oxide in a MOS structure?
  2. In the Deal-Grove model, what is the relationship between oxide thickness and time early in thermal oxidation, while the oxide is still thin?
  3. Which generally describes the thickness relationship between the field oxide used for isolation such as LOCOS and the gate oxide of a MOSFET?
  4. What is the common definition of the "junction depth" of a PN junction?
  5. What is the phenomenon called in which boron and phosphorus diffuse faster during silicon oxidation than without oxidation?