Emerging memories

In cross-point memories such as PCM, which chalcogenide device, placed in series with the storage element as a selector, suddenly conducts above a certain voltage?

  1. AOTS (ovonic threshold switch)
  2. BZener diode
  3. CFloating gate
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Answer: A. OTS (ovonic threshold switch)

An OTS (ovonic threshold switch) is a chalcogenide device that suddenly becomes low-resistance above its threshold voltage and returns to high resistance when the voltage drops. This nonlinear behavior makes it a selector that suppresses sneak currents into unselected cells. Unlike PCM, it does not store a state.

  • A. Correct. It is a chalcogenide threshold switch.
  • B. A Zener diode uses reverse breakdown and is not a typical cross-point selector.
  • C. A floating gate is the charge-storing electrode of flash memory.
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More Emerging memories questions

  1. Why must the read current be limited in STT-MRAM?
  2. Which device uses the fact that the tunneling current through a thin ferroelectric layer depends on the direction of its polarization?
  3. Which effect, being studied to reduce MRAM write energy, changes the magnetic anisotropy of a magnetic layer with a voltage?
  4. Which correctly describes how MRAM stores data?
  5. Which correctly describes how phase-change memory (PCM) stores data?