Semiconductor physics

Which statement is correct when boron (B) is added to silicon as an impurity?

  1. AIt is electrically inactive and does not change the conductivity type
  2. BIt acts as a donor and the silicon becomes n-type
  3. CIt acts as an acceptor and the silicon becomes p-type
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Answer: C. It acts as an acceptor and the silicon becomes p-type

Boron is a group III element with three valence electrons, so one electron is missing from the covalent bonds in silicon, and it accepts an electron from its surroundings. This creates a hole in the valence band, so boron acts as an acceptor and the silicon becomes p-type.

  • A. Boron is a typical, electrically active acceptor in silicon.
  • B. Group V elements such as phosphorus and arsenic act as donors.
  • C. Correct. Group III boron becomes an acceptor.
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More Semiconductor physics questions

  1. What are the majority carriers in a p-type semiconductor?
  2. Which of the following materials has the largest band gap?
  3. Which is the correct unit of carrier mobility?
  4. With electron density n, hole density p, electron mobility μn, hole mobility μp and elementary charge q, which expression gives the conductivity σ of a semiconductor?
  5. What is the process called in which electrons and holes recombine through deep levels (traps) in the band gap?