Ion implantation

What is the main advantage of ion implantation over thermal diffusion?

  1. AIt can be done at low temperature, with precise control of dose and depth
  2. BIt allows long processing at high temperature
  3. CIt causes no crystal damage at all
Show answer and explanation

Answer: A. It can be done at low temperature, with precise control of dose and depth

Ion implantation can be done near room temperature, so photoresist can be used as a mask, and the dose is precisely controlled by measuring current. Depth is also controlled by energy. On the other hand, it damages the crystal, so annealing is needed afterward.

Practice this topic Back to topic

More Ion implantation questions

  1. What is the purpose of pre-amorphization implantation (PAI)?
  2. What is used to suppress wafer charging (charge-up) during ion implantation?
  3. Singly charged ions are implanted into a wafer area of 100 cm² at a dose of 1×10¹⁵ ions/cm². With a beam current of 1 mA, approximately how long does the implant take? (Elementary charge 1.6×10⁻¹⁹ C)
  4. In CMOS well formation, what is a well called in which high-energy implantation makes the dopant concentration higher deep below the surface?
  5. What is the main purpose of halo (pocket) implants, which implant dopants of the same type as the channel at an angle near the source/drain edges?