Ion implantation

What is the principle of ion implantation?

  1. AIonizing the impurity, accelerating it with an electric field and driving it into the wafer
  2. BImmersing the wafer in a liquid containing the impurity
  3. CHeating the wafer in a gas containing the impurity so it soaks in from the surface
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Answer: A. Ionizing the impurity, accelerating it with an electric field and driving it into the wafer

In ion implantation, impurities such as boron or phosphorus are ionized, accelerated by an electric field and driven into the wafer at high speed. The acceleration energy precisely controls the depth, and the number of ions implanted (the dose) controls the concentration.

  • A. Correct. Ions are accelerated and implanted.
  • B. Immersing in a liquid is not ion implantation.
  • C. Heating in a gas so the impurity soaks in is thermal diffusion.
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More Ion implantation questions

  1. Which unit is commonly used to express the acceleration energy in ion implantation?
  2. Which correctly pairs dopants implanted into silicon with the conductivity type they produce?
  3. Which is closest to the range of ion implantation doses used in LSI manufacturing?
  4. What is the main reason the beam path in an ion implanter is kept at high vacuum?
  5. In a typical ion implanter, in what order do ions pass through the system?