Semiconductor physics

In lightly doped silicon, what is the main reason mobility decreases as temperature rises?

  1. AThe number of impurities increases
  2. BThe number of carriers decreases
  3. CScattering by lattice vibrations (phonons) increases
Show answer and explanation

Answer: C. Scattering by lattice vibrations (phonons) increases

As temperature rises, the atoms in the crystal vibrate more strongly, and carriers are scattered more often, so mobility decreases. In heavily doped material, impurity scattering also becomes important, and it dominates at low temperatures.

Practice this topic Back to topic

More Semiconductor physics questions

  1. Which value is closest to the intrinsic carrier density of silicon at room temperature?
  2. Which value is closest to the atomic density of crystalline silicon?
  3. Which correctly describes a hole?
  4. Which value is closest to the band gap of germanium (Ge) at room temperature?
  5. How many valence (outermost-shell) electrons does a silicon atom have?