Field Effect Transistors

Part 2: MOSFET Transistors

The Metal gate is insulated by a layer of silicon Oxide from the Semiconductor of the n-channel or p-channel. This prevents gate current from flowing, reducing power usage.

MOSFET off

MOSFET on

For a great animated demonstration of how a MOSFET transistor is manufactured and operates go to Molecular Expressions: Electricity and Magnetism Tutorials.

Symbols

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Enhancement Mode

Since the gate is insulated from the channel, N-channel MOSFETs can operate with a positive gate voltage, which increases current flow. This is called enhancement mode.