Metrology and analysis

Which method, without forming electrodes, deposits charge on the wafer surface by corona discharge and measures changes in surface potential to evaluate oxide and interface electrical properties?

  1. AFour-point probe
  2. BX-ray diffraction
  3. CContactless electrical evaluation using corona charging (such as COCOS)
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Answer: C. Contactless electrical evaluation using corona charging (such as COCOS)

Depositing charge on the wafer by corona discharge and measuring surface potential contactlessly with a Kelvin probe allows oxide thickness, charge, interface states, leakage and more to be evaluated without building MOS structures. Because no gate electrode is needed, it is used for in-line monitoring.

  • A. The four-point probe is a contact method for resistivity.
  • B. X-ray diffraction examines crystal structure.
  • C. Correct. Corona charging and surface potential measurement are used.
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