Ion implantation

When implanting with the wafer tilted, what is the phenomenon called in which areas in the shadow of tall patterns such as resist receive no implant?

  1. AChanneling
  2. BGettering
  3. CShadowing
Show answer and explanation

Answer: C. Shadowing

When the wafer is tilted, for example to prevent channeling or for halo implants, ions cannot reach areas in the shadow of tall resist or gates. This is called shadowing, and because it makes the implanted regions asymmetric, techniques such as rotating the wafer and implanting from several directions are used.

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More Ion implantation questions

  1. When dopants are activated by annealing, which property sets the upper limit of the concentration that can be electrically activated?
  2. Which is a characteristic of laser annealing?
  3. In ion implantation, how is the dose made uniform across the wafer?
  4. In an ion implanter, which component measures the beam current to determine the number of implanted ions (dose)?
  5. When forming shallow p-type junctions, what is the main purpose of implanting carbon or similar species together with boron (co-implantation)?