Computer Science I / Semiconductors and Transistors
Practice question · Multiple choice

Transistors are approaching a few nanometres, where electrons tunnel through barriers meant to block them. Why is that a fundamental obstacle rather than a manufacturing one?

Hints
  1. Ask whether a better factory could stop an electron from tunnelling.
  2. The barrier is doing its job perfectly and the electron appears on the other side anyway. What does that mean?
Show the answer

C. Because tunnelling is a property of matter, not a defect

Why

Tunnelling is what electrons do at those scales, so a flawless barrier still leaks and the current is wasted as heat. It is the physics setting the limit rather than the process, which is why the industry moved to FinFET and gate-all-around geometries, changing the shape rather than continuing to shrink.

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