Advanced transistors (FinFET and GAA)

In manufacturing nanosheet GAA transistors, why is only the SiGe selectively removed from stacked alternating Si and SiGe layers?

  1. ATo make the transistor lighter
  2. BSo that the gate insulator and gate electrode can be filled into the gaps, surrounding each Si nanosheet with the gate
  3. CBecause SiGe does not conduct electricity
Show answer and explanation

Answer: B. So that the gate insulator and gate electrode can be filled into the gaps, surrounding each Si nanosheet with the gate

In nanosheet GAA, after the Si/SiGe stack is patterned, only the SiGe is selectively etched away, leaving the Si sheets suspended. Filling the gaps with a high-k film and metal gate creates a structure in which each sheet is surrounded by the gate on all sides.

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More Advanced transistors (FinFET and GAA) questions

  1. What is the cause of self-heating, which tends to be a problem in FinFETs and SOI transistors?
  2. In highly scaled transistors, which factors are becoming increasingly important limits on performance?
  3. Which correctly describes materials such as molybdenum disulfide (MoS2), researched as channel materials for future ultra-small transistors?
  4. What is the main purpose of growing raised crystal on the fins in the source and drain of a FinFET by epitaxial growth?
  5. What is the basic way to reduce metal-semiconductor contact resistance?