OE-10.1 Introduction to MOS Technology
You can explain basic MOS transistor action, distinguish enhancement from depletion mode, and account for threshold voltage and the body effect.
Everything in VLSI rests on one device behaving as a voltage-controlled switch, so time spent on the MOS transistor here pays back through every later unit. Threshold voltage is the number that decides when the switch turns on, and the body effect is why it is not a constant - source-to-body bias shifts it, which matters the moment you stack transistors in series. Enhancement and depletion mode differ in whether the channel exists at zero gate voltage; nearly all modern logic is enhancement mode.
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Basic MOS transistor action
How the transistor this whole subject is built from actually works. Everything above it in the stack assumes this item, so it is worth the time.
Enhancement mode operation
The normal mode, where a channel has to be created before current flows. It is the device nearly all modern logic uses.
Depletion mode operation
The other mode, where the channel exists until it is removed. It appears mainly as a load in older circuits, which the inverter topic shows.
Basic electrical properties of MOS devices
The electrical parameters that matter for design rather than for physics. These are the numbers that appear in every later calculation.
Threshold voltage
The voltage at which the device turns on, which sets the supply voltage and the noise margin. It is the single most quoted parameter of the device.
The body effect
How that threshold shifts when the source is not at substrate potential. It matters in stacked circuits, which is most of the logic in the topics below.
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