The Transistor as a Valve

10 atomic recall cards. Export to Anki and let spaced repetition do its slow work.

In Anki: File → Import, choose this TSV, set field separator to Tab, deck = Sand to Silicon · Ch 18, note type = Basic.

Front	Back
What does MOSFET stand for?	Metal-oxide-semiconductor field-effect transistor.
What are the four physical regions of a MOSFET?	Source, channel, drain, and gate.
What is the doping type of the source and drain vs. the channel in an n-channel MOSFET?	Source and drain are heavily n-doped (full of free electrons); the channel between them is p-doped (full of holes, empty of free electrons).
What is the approximate threshold voltage of a modern MOSFET?	Around 0.4–0.7 V.
How thick is the gate oxide in a leading-edge MOSFET?	Roughly 1 nm — about three atoms of silicon dioxide stacked on top of each other.
How fast does a modern MOSFET switch?	Around 1 picosecond (10⁻¹² seconds).
How much energy does it take to flip a modern transistor once?	Around 10⁻¹· joules — small enough to flip it a hundred trillion times on the energy of a single calorie.
How many transistors are in a single Rubin GPU package?	On the order of 336 billion.
What is the approximate gate length (channel length) in a leading-edge node?	Around 15 nanometers, even though the node is marketed as “3 nm” or “2 nm” — the naming convention is now marketing, not measurement.
What did the FinFET solve that the planar MOSFET could not below 22 nm?	The gate could no longer control the channel in a planar design; electrons leaked when the transistor was off. FinFET wraps the gate around three sides of a vertical fin for better electrostatic grip.