Diode Definition of Terms

Defining Terms

Acceptor: Ionized, negative-charged immobile dopant atom (ion) in a p-type semiconductor after the release of a hole.

Avalanche breakdown: In the reverse-biased diode, hole–electron pairs are generated in the depletion region by ionization, thus by the lattice collision with energetic electrons and holes.

Bandgap energy: Energy difference between the conduction band and the valence band in a semiconductor.

Barrier voltage: A voltage which develops across the junction due to uncovered immobile ions on both sides of the junction. Ions are uncovered due to the diffusion of mobile carriers across the junction.

Boltzmann relation: Relates the density of particles in one region to that in an adjacent region, with the potential energy between both regions.

Carrier lifetime: Time an injected minority carrier travels before its recombination with a majority carrier.

Concentration gradient: Difference in carrier concentration.

Diffusion: Movement of free carriers in a semiconductor caused by the difference in carrier densities (concentration gradient). Also movement of dopands during fabrication of diffused diodes.

Diffusion capacitance: Change in charge of injected carriers corresponding to change in forward bias voltage in a diode.

Diffusion constant: Product of the thermal voltage and the mobility in a semiconductor.

Donor: Ionized, positive-charged immobile dopant atom (ion) in an n-type semiconductor after the release of an electron.

Drift: Movement of free carriers in a semiconductor due to the electric field.

Ideality factor: The factor determining the deviation from the ideal diode characteristic m = 1. At small and large currents m ≈ 2.

Incremental model: Small-signal differential (incremental) semiconductor diode equivalent RC circuit of a diode, biased in a dc operating point.

Incremental resistance: Small-signal differential (incremental) resistance of a diode, biased in a dc operating point.

Junction capacitance: Change in charge of immobile ions in the depletion region of a diode corresponding to a change in reverse bias voltage on a diode.

Majority carriers: Holes are in majority in a p-type semiconductor; electrons are in majority in an n-type semiconductor.

Minority carriers: Electrons in a p-type semiconductor are in minority; holes are in majority. Similarly, holes are in minority in an n-type semiconductor and electrons are in majority.

Reverse breakdown: At the reverse breakdown voltage the diode can conduct a large current in the reverse direction.

Reverse generation-recombination current: Part of the reverse current in a diode caused by the generation of hole–electron pairs in the depletion region. This current is voltage dependent because the depletion region width is voltage dependent.

Reverse saturation current: Part of the reverse current in a diode which is caused by diffusion of minority carriers from the neutral regions to the depletion region. This current is almost independent of the reverse voltage.

Temperature coefficient: Relative variation ΔX/X of a value X over a temperature range, divided by the difference in temperature ΔT.

Zener breakdown: In the reverse-biased diode, hole–electron pairs are generated by a large electric field in the depletion region.

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