EE477L MOS VLSI Circuit Design

A collection of vocabulary flashcards focused on key terms related to MOS VLSI Circuit Design, particularly surrounding MOSFET theory.

MOSFET

Metal Oxide Semiconductor Field Effect Transistor, a unipolar device that allows control of electrical current.

BJT

Bipolar Junction Transistor, a type of transistor that relies on both electrons and holes for its operation.

Band gap

The energy difference between the top of the valence band and the bottom of the conduction band.

Fermi level

The energy level at which the probability of finding an electron is 50% at absolute zero temperature.

Accumulation mode

A mode of operation where holes are induced at the silicon-oxide interface in an n-MOS transistor.

Depletion mode

A mode of operation where the interface is depleted of mobile charge carriers in an n-MOS transistor.

Enhancement mode

A mode of operation where a transistor is normally off and requires a gate voltage to conduct.

Depletion mode (transistor)

A type of transistor that is normally on and can be turned off by applying negative gate voltage.

Threshold voltage (VT)

The minimum gate-to-source voltage that is required to create a conducting path between the source and drain of a MOSFET.

Subthreshold current

The current that flows through a MOSFET when the gate-to-source voltage is below the threshold voltage.

Hot carrier effect

A phenomenon where high-energy carriers can get injected into the gate oxide, potentially causing device degradation.

Punch-through

A situation in small geometry devices where the depletion regions of the source and drain merge, leading to uncontrolled current.

Velocity saturation

The condition when the drift velocity of charge carriers in a semiconductor reaches a maximum limit due to high electric fields.

Channel length modulation

A phenomenon where the effective length of the channel in a MOSFET is reduced under saturation conditions, affecting current.

Junction capacitance

The capacitance associated with the depletion region of a pn-junction, which varies with bias voltage.

Body effect

The effect on threshold voltage due to a change in the substrate bias, which alters the depletion region.

Parasitic capacitance

Unintended capacitance that occurs between different parts of a MOSFET which can affect its performance.

Work function

The minimum energy required to remove an electron from a solid to a point in the vacuum just outside the solid surface.