Ion implantation

When dopants are activated by annealing, which property sets the upper limit of the concentration that can be electrically activated?

  1. ASolid solubility
  2. BMobility
  3. CPermittivity
Show answer and explanation

Answer: A. Solid solubility

The maximum concentration of a dopant that can dissolve in the crystal is its solid solubility. Even if dopants are implanted above it, the excess precipitates or forms clusters and does not become electrically active. Anneals that reach high temperatures very briefly can sometimes achieve activation temporarily above solid solubility.

Practice this topic Back to topic

More Ion implantation questions

  1. Which is a characteristic of laser annealing?
  2. In ion implantation, how is the dose made uniform across the wafer?
  3. In an ion implanter, which component measures the beam current to determine the number of implanted ions (dose)?
  4. When forming shallow p-type junctions, what is the main purpose of implanting carbon or similar species together with boron (co-implantation)?
  5. Which gas is typically used in the ion source of an implanter to produce boron ions?