Ion implantation

Which correctly pairs the distribution that approximates the depth profile of implanted dopants with the term for the depth of its peak?

  1. AUniform distribution; the peak is always at the surface
  2. BGaussian distribution; the peak depth is called the projected range (Rp)
  3. CExponential distribution; the peak depth is called the diffusion length
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Answer: B. Gaussian distribution; the peak depth is called the projected range (Rp)

The profile of implanted dopants is approximated by a Gaussian distribution, with the peak depth called the projected range Rp and the spread given by the standard deviation ΔRp. Rp is determined by the acceleration energy and ion species. In reality, channeling and other effects can extend the tail toward greater depth.

Depth profile of implanted dopants Depth Surface Dopant concentration Rp (projected range) ΔRp (straggle) Peak Channeling tail
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More Ion implantation questions

  1. In an ion implanter, which part uses a magnetic field to select only the desired ion species?
  2. What is the main advantage of ion implantation over thermal diffusion?
  3. What is the purpose of pre-amorphization implantation (PAI)?
  4. What is used to suppress wafer charging (charge-up) during ion implantation?
  5. 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)