Ion implantation

If dopants with a dose of 1×10¹⁵ cm⁻² are distributed uniformly over a depth of 100 nm, what is the approximate average concentration?

  1. A1×10¹⁸ cm⁻³
  2. B1×10²² cm⁻³
  3. C1×10²⁰ cm⁻³
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Answer: C. 1×10²⁰ cm⁻³

Concentration is dose ÷ depth. Since 100 nm = 1×10⁻⁵ cm, 1×10¹⁵ ÷ 1×10⁻⁵ = 1×10²⁰ cm⁻³. Heavily doped regions such as sources and drains have concentrations of about this level.

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More Ion implantation questions

  1. Which ion implantation is used for wafer splitting (Smart Cut) and for lifetime control in power devices?
  2. When an amorphized layer is recrystallized, what are the defects called that remain slightly deeper than the original boundary between the amorphous layer and the crystal?
  3. What is the principle of ion implantation?
  4. Which unit is commonly used to express the acceleration energy in ion implantation?
  5. Which correctly pairs dopants implanted into silicon with the conductivity type they produce?