Ion implantation

Which is a common way to suppress channeling (ions traveling too deep through gaps in the crystal) in ion implantation?

  1. AUsing the maximum acceleration energy
  2. BCleaning the wafer after implantation
  3. CTilting the wafer a few degrees from the crystal axis during implantation
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Answer: C. Tilting the wafer a few degrees from the crystal axis during implantation

When ions enter along rows of atoms in the crystal, they travel through gaps where they rarely collide and penetrate deeper than intended. Tilting the wafer a few degrees (for example, 7°) from the crystal axis or implanting through a thin surface film suppresses channeling.

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More Ion implantation questions

  1. Which unit is used for the dose in ion implantation?
  2. Which is a correct technique for forming shallow junctions for the sources and drains of scaled transistors?
  3. Which correctly pairs the distribution that approximates the depth profile of implanted dopants with the term for the depth of its peak?
  4. In an ion implanter, which part uses a magnetic field to select only the desired ion species?
  5. What is the main advantage of ion implantation over thermal diffusion?