Advanced transistors (FinFET and GAA)

What is an effect of quantum confinement when fins or nanosheets are thinned to a few nanometers?

  1. AThe effective band gap increases and the threshold voltage shifts (thickness variation becomes threshold voltage variation)
  2. BThe charge of the electron increases
  3. CSilicon turns into a metal
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Answer: A. The effective band gap increases and the threshold voltage shifts (thickness variation becomes threshold voltage variation)

When the channel is only a few nanometers thick, electron energies are quantized into discrete levels and the lowest level rises, enlarging the effective band gap. The threshold voltage shifts as a result, and small variations in thickness become variations in threshold voltage.

  • A. Correct. The effective band gap grows and the threshold voltage changes.
  • B. The charge of a single electron does not change.
  • C. Silicon does not become a metal.
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More Advanced transistors (FinFET and GAA) questions

  1. In a FinFET made in the usual orientation on a (100) wafer, the fin sidewalls that form the channel are mainly (110) planes. What is the effect on mobility?
  2. Which correctly describes the structure of a FinFET?
  3. Which correctly describes a GAA (gate-all-around) transistor?
  4. Which describes a short-channel effect in MOSFETs?
  5. What is the main reason for using high-k (high-dielectric-constant) materials for the gate insulator?