Advanced transistors (FinFET and GAA)

Which transistor has a source, channel and drain of the same conductivity type and doping, with no PN junctions?

  1. ABipolar transistor
  2. BIGBT
  3. CJunctionless transistor
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Answer: C. Junctionless transistor

A junctionless transistor uniformly dopes a thin silicon nanowire or similar throughout and turns off the current by having the gate deplete the channel from around it. Because no abrupt PN junctions need to be formed, it is researched as being easier to scale, but challenges such as threshold voltage variation remain.

  • A. A bipolar transistor has two PN junctions.
  • B. An IGBT has a structure with multiple PN junctions.
  • C. Correct. It is a transistor without PN junctions.
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More Advanced transistors (FinFET and GAA) questions

  1. 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)?
  2. Which correctly describes the "scale length (natural length) λ" used to estimate the severity of short-channel effects?
  3. What is an effect of quantum confinement when fins or nanosheets are thinned to a few nanometers?
  4. 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?
  5. Which correctly describes the structure of a FinFET?