Semiconductor Electronics: Materials, Devices and Simple Circuits

Vocabulary practice flashcards reviewing fundamental concepts, properties, and equations from the Semiconductor Electronics lecture notes.

Metals (Resistivity and Conductivity Range)

Materials possessing very low resistivity ($\rho \sim 10^{-2} \text{ to } 10^{-8}\,\Omega\,\text{m}$) and high conductivity ($\sigma \sim 10^{2} \text{ to } 10^{8}\,\text{S}\,\text{m}^{-1}$).

Semiconductors (Resistivity and Conductivity Range)

Materials with resistivity ($\rho \sim 10^{-2} \text{ to } 10^{6}\,\Omega\,\text{m}$) or conductivity ($\sigma \sim 10^{2} \text{ to } 10^{-6}\,\text{S}\,\text{m}^{-1}$) intermediate to metals and insulators.

Insulators (Resistivity and Conductivity Range)

Materials having high resistance or resistivity ($\rho \sim 10^{11} \text{ to } 10^{19}\,\Omega\,\text{m}$) and low conductivity ($\sigma \sim 10^{-11} \text{ to } 10^{-19}\,\text{S}\,\text{m}^{-1}$).

Forbidden Energy Gap (FEG)

The energy gap between the conduction band minimum and valence band maximum ($\Delta E_g = (CB)_{\text{min}} - (VB)_{\text{max}}$) where free electrons cannot exist.

Holes

Unfilled energy levels left in the valence band when an electron leaves for the conduction band; they act mathematically as positive charge carriers.

Intrinsic Semiconductor

A pure semiconductor made up of a single element (such as Silicon or Germanium) or pure compound without added impurities.

Intrinsic Carrier Concentration ($n_i$)

The carrier concentration in a pure semiconductor where the number of thermally generated electrons ($n_e$) equals the number of holes ($n_p$ or $n_h$), written as $n_e = n_h = n_i$.

Doping

The process of deliberate addition of a very small amount of suitable impurity (dopants) into an intrinsic semiconductor to increase its electrical conductivity.

Dopants

Impurity atoms deliberately added into an intrinsic semiconductor to alter its charge carrier concentration.

Extrinsic Semiconductor

A semiconductor containing added impurity atoms (dopants), also referred to as an impure semiconductor.

Pentavalent Dopants

Impurity elements with valency 5 (such as Arsenic, Antimony, and Phosphorus) used to create N-type semiconductors.

Trivalent Dopants

Impurity elements with valency 3 (such as Indium, Boron, and Aluminium) used to create P-type semiconductors.

N-Type Semiconductor

An extrinsic semiconductor formed by doping tetravalent Si or Ge with pentavalent donor impurities, resulting in free electrons as majority carriers ($n_e \gg n_h$) and holes as minority carriers.

P-Type Semiconductor

An extrinsic semiconductor formed by doping tetravalent Si or Ge with trivalent acceptor impurities, resulting in holes as majority carriers ($n_h \gg n_e$) and electrons as minority carriers.

Mass Action Law

A fundamental equation for semiconductors in thermal equilibrium stating that the product of electron concentration ($n_e$) and hole concentration ($n_h$) equals the square of the intrinsic carrier concentration ($n_i^2$): $n_e n_h = n_i^2$.

Drift Velocity ($v_d$)

The average velocity gained by free charge carriers under the influence of an applied electric field $E$, given by $v_d = \mu E$, where $\mu$ is mobility.

Current Density ($J$)

Electric current per unit cross-sectional area ($J = I/A$), expressed in terms of charge carriers as $J = n e v_d = n e \mu E = \sigma E$.

Electron Mobility vs. Hole Mobility

In semiconductors, electron mobility ($\mu_e$) is greater than hole mobility ($\mu_h$) ($\mu_e > \mu_h$) because electrons move in the conduction band while holes move in the valence band.

Band Gap of Silicon ($E_g$)

The energy band gap for a Silicon crystal, which is $1.1\,\text{eV}$.

Band Gap of Germanium ($E_g$)

The energy band gap for a Germanium crystal, which is $0.7\,\text{eV}$ (or $0.74\,\text{eV}$ in detailed band structures).