Metrology and analysis

Which analysis method field-evaporates atoms one by one from the tip of a needle-shaped specimen and detects their positions and identities to map the 3D distribution of atoms such as dopants?

  1. AAtom probe tomography
  2. BOptical microscopy
  3. CScanning acoustic microscopy
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Answer: A. Atom probe tomography

In an atom probe, a specimen shaped into a needle by FIB is subjected to high voltage and pulses so that tip atoms leave one at a time as ions; their arrival positions and times at the detector reveal element types and original positions. The 3D distribution of dopants inside transistors and similar can be examined at the atomic level.

  • A. Correct. Atoms are removed one by one to map their 3D distribution.
  • B. Optical microscopes cannot show atomic distributions.
  • C. Acoustic microscopes examine delamination inside packages and the like.
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