Ion implantation

Which type of ion implanter is mainly used for medium-dose implants such as MOSFET threshold-voltage adjustment and wells?

  1. ACMP tool
  2. BMedium-current implanter
  3. CElectron-beam writer
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Answer: B. Medium-current implanter

Ion implanters are broadly divided by dose and energy range into medium-current (threshold adjust, halo implants and so on), high-current (high-dose implants such as source/drain) and high-energy (deep wells and so on). Medium-current tools excel at dose accuracy and implant-angle control.

  • A. A CMP tool planarizes by polishing.
  • B. Correct. It is used for medium-dose implants.
  • C. An electron-beam writer draws patterns.
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More Ion implantation questions

  1. What is the pair of a vacancy and an interstitial atom called, created in the crystal when an implanted ion knocks a silicon atom out of place?
  2. Why is the wafer cooled during high-current ion implantation?
  3. What is the typical distribution of crystal damage created by ion implantation?
  4. What method has commonly been used to introduce impurities into a MOSFET's polysilicon gate electrode to lower its resistance?
  5. What is the technique of implanting n-type impurities into an already p-type region to lower the net doping or invert the conductivity type called?