Advanced transistors (FinFET and GAA)

In nanosheet GAA transistors now in production, how many nanosheets are typically stacked in one transistor?

  1. A1
  2. BAbout 3
  3. CAbout 100
Show answer and explanation

Answer: B. About 3

Current nanosheet GAA transistors typically stack about three sheets. More sheets increase current in the same footprint, but lower sheets suffer more from distance to the source/drain and parasitic capacitance, and fabrication gets harder, so the count balances benefit against difficulty.

  • A. A single sheet would forgo the current gain from stacking.
  • B. Correct. About three is typical.
  • C. Stacking 100 sheets is not realistic for logic transistors.
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More Advanced transistors (FinFET and GAA) questions

  1. Which structure places nMOS and pMOS nanosheets close together on either side of a thin insulating wall to reduce cell area?
  2. What is the state called in which the channel is so short that carriers travel from source to drain almost without scattering?
  3. Which transistor has a source, channel and drain of the same conductivity type and doping, with no PN junctions?
  4. In FinFETs built on bulk substrates, what is the purpose of a heavily doped layer at the base of the fin (the part the gate controls poorly)?
  5. Which correctly describes the "scale length (natural length) λ" used to estimate the severity of short-channel effects?