Semiconductor Physics Flashcards

Flashcards on semiconductor physics, atom structure, energy bands, silicon structure, doping, drift and diffusion currents, and PN junctions.

Semiconductor

Material whose electrical conductivity is between that of a conductor and an insulator. Common examples include silicon, germanium, and some compounds.

Alessandro Volta

An early scientist who noted the existence of materials with properties we now associate with semiconductors in the late 18th century.

Rutherford's Experiment (1911)

Demonstrated that most of the mass of an atom and its positive charge are concentrated in a central nucleus.

Bohr's Model (1913)

Introduced the concept of stationary orbits where electrons do not emit energy, resolving inconsistencies in Rutherford's model.

Planck's Quantum Theory

States that energy radiation from an atomic system occurs in discrete emissions according to the equation E = nhν.

Energy Bands

Quasi-continuous distributions of energy levels that arise when atoms are grouped together, such as in a crystal lattice.

Valence Band

The energy band containing electrons that form bonds between atoms in a crystal.

Conduction Band

The energy band where electrons are free to move under the influence of an electric field.

Energy Gap (GAP)

The forbidden band of energy separating the valence and conduction bands.

Silicon (Si)

The most commonly used semiconductor material in electronics.

Covalent Bond

A chemical bond formed by the sharing of electrons between atoms, as seen in silicon crystal structures.

Hole

A positive charge carrier in a semiconductor, representing the absence of an electron in a covalent bond.

Electron-Hole Pair

Simultaneous creation of a free electron and a hole when a covalent bond is broken.

Drift Velocity

The average velocity of charge carriers in a material due to an electric field.

Mobility

Measure of how easily a charge carrier moves through a material under the influence of an electric field, measured in m²/V·s.

Intrinsic Semiconductor

A pure semiconductor material without any doping.

Doping

The process of introducing impurities into a semiconductor to alter its electrical properties.

N-type Semiconductor

A semiconductor doped with pentavalent impurities, resulting in an excess of free electrons.

Donors

Impurities in an N-type semiconductor that donate free electrons.

Majority Carriers (N-type)

Electrons in an N-type semiconductor.

Minority Carriers (N-type)

Holes in an N-type semiconductor.

P-type Semiconductor

A semiconductor doped with trivalent impurities, resulting in an excess of holes.

Acceptors

Impurities in a P-type semiconductor that accept electrons, creating holes.

Majority Carriers (P-type)

Holes in a P-type semiconductor.

Minority Carriers (P-type)

Electrons in a P-type semiconductor.

Drift Current

Current due to the movement of charge carriers under the influence of an electric field.

Diffusion Current

Current due to the movement of charge carriers from regions of high concentration to regions of low concentration.

PN Junction

Formed by joining a P-type and an N-type semiconductor, creating a diode-like behavior.

Depletion Layer

A region near the PN junction that is depleted of free charge carriers.

Potential Barrier (Vb)

Electric potential difference across the depletion region of a PN junction.

Forward Bias

Applying voltage to a PN junction with the positive terminal to the P-side and negative to the N-side, reducing the potential barrier.

Reverse Bias

Applying voltage to a PN junction with the positive terminal to the N-side and negative to the P-side, increasing the potential barrier.

Transition Capacitance (CT)

Capacitance associated with the depletion region of a PN junction under reverse bias.

Diffusion Capacitance

Capacitance that arises in a forward-biased PN junction due to the storage of charge carriers.