Basic Semiconductor Devices and Atomic Structure – Vocabulary Flashcards

These vocabulary flashcards cover fundamental atomic structure, semiconductor physics, diode behavior, rectification, filtering, regulation, specialized diodes, and basic BJT operation, providing a concise reference for key terms introduced in the lecture.

Atom

Smallest particle of an element that retains the element’s properties.

Electron

Negatively charged subatomic particle that orbits an atom’s nucleus.

Proton

Positively charged particle found in an atom’s nucleus.

Neutron

Neutral particle located in an atom’s nucleus.

Nucleus

Central region of an atom containing protons and neutrons.

Atomic Number

Number of protons in the nucleus; identifies an element.

Bohr Model

Planetary model of the atom with electrons in circular orbits.

Quantum Model

Statistical atomic model using probability clouds and orbitals.

Electron Shell

Grouping of electron orbits with the same energy level.

Energy Level

Discrete energy value associated with a specific electron shell.

Valence Electron

Electron in the outermost shell; determines bonding and electrical properties.

Ionization

Process of removing or adding electrons to create an ion.

Free Electron

Electron that has escaped an atom and can conduct current.

Ion

Atom or group of atoms with a net electric charge.

Conductor

Material with many free electrons that easily conducts current (e.g., Cu, Ag).

Insulator

Material with tightly bound electrons that resists current flow (e.g., glass, rubber).

Semiconductor

Material whose conductivity lies between conductors and insulators (e.g., Si, Ge).

Band Gap

Energy difference between the valence band and conduction band.

Valence Band

Energy band containing the outer-shell (valence) electrons.

Conduction Band

Energy band where free electrons move through a solid.

Silicon

Four-valence-electron semiconductor widely used in electronics.

Germanium

Semiconductor similar to silicon but with higher intrinsic carrier concentration.

Covalent Bond

Bond formed by sharing valence electrons between atoms.

Crystal

Symmetrical three-dimensional arrangement of atoms in a solid.

Intrinsic Semiconductor

Pure semiconductor with no intentional impurities.

Doping

Adding impurity atoms to a semiconductor to change its conductivity.

N-type Semiconductor

Doped material with excess electrons as majority carriers (donor doping).

P-type Semiconductor

Doped material with excess holes as majority carriers (acceptor doping).

Donor Atom

Pentavalent impurity that donates an extra electron (e.g., P, As).

Acceptor Atom

Trivalent impurity that creates a hole (e.g., B, Ga).

Majority Carrier

Most plentiful charge carrier in a doped semiconductor (electrons in n-type, holes in p-type).

Minority Carrier

Less plentiful carrier type in a semiconductor.

PN Junction

Boundary between p-type and n-type regions in a crystal.

Depletion Region

Charge-depleted zone around a PN junction containing fixed ions.

Barrier Potential

Built-in junction voltage that opposes carrier diffusion (~0.7 V Si, 0.3 V Ge).

Forward Bias

External voltage that reduces the barrier potential and allows current through a diode.

Reverse Bias

Voltage polarity that widens the depletion region and blocks current.

Reverse Breakdown

Condition where a diode conducts heavily in reverse after a threshold voltage.

Avalanche Effect

Carrier multiplication process causing diode breakdown at high reverse voltage.

Diode

Two-terminal PN-junction device that conducts in one direction.

Rectifier

Circuit or device that converts AC to DC using diodes.

Half-Wave Rectifier

Rectifier that passes one half-cycle of an AC input.

Full-Wave Rectifier

Rectifier that converts both AC half-cycles to pulsating DC.

Peak Inverse Voltage (PIV)

Maximum reverse voltage a diode must withstand.

Capacitor-Input Filter

Filter using a capacitor to reduce rectifier ripple.

Ripple Voltage

Residual AC variation on a filtered DC output.

Ripple Factor

Ratio of ripple voltage to DC output; indicates filter effectiveness.

Voltage Regulator

Circuit or device that maintains a constant output voltage.

Line Regulation

Change in output voltage caused by a change in input voltage.

Load Regulation

Change in output voltage caused by a change in load current.

Zener Diode

Diode designed to operate in reverse breakdown for voltage regulation.

Zener Breakdown

Low-voltage breakdown due to intense electric field in a heavily doped junction.

Temperature Coefficient (Zener)

Rate at which zener voltage changes with temperature.

Varactor Diode

Reverse-biased diode used as a voltage-controlled capacitor.

Light-Emitting Diode (LED)

Forward-biased diode that emits photons via electroluminescence.

Electroluminescence

Light emission resulting from electron-hole recombination in a semiconductor.

High-Intensity LED

LED optimized for high luminous output used in lighting and displays.

Organic LED (OLED)

Light-emitting device using organic layers between electrodes.

Quantum Dot

Nanoscale semiconductor crystal whose band gap varies with size, used for tunable light emission.

Photodiode

Reverse-biased diode that generates current proportional to light intensity.

Schottky Diode

Fast-switching metal-semiconductor diode with low forward drop (~0.3 V).

PIN Diode

Diode with an intrinsic layer between p and n regions; used in RF switching and photodetection.

Tunnel Diode

Heavily doped PN junction exhibiting negative resistance for microwave oscillators.

Current-Regulator Diode

Two-terminal device that maintains a nearly constant current over a range of voltages.

Bipolar Junction Transistor (BJT)

Three-layer, three-terminal device (emitter, base, collector) that amplifies current.

Emitter (BJT)

Heavily doped region that injects carriers into the base.

Base (BJT)

Very thin, lightly doped region that controls transistor action.

Collector (BJT)

Region that collects carriers; moderately doped and largest area.

βDC (hFE)

DC current gain of a BJT; ratio of collector current to base current.

αDC

BJT parameter equal to collector current divided by emitter current (≈0.99).

Cutoff (BJT)

Operating state where both junctions are reverse-biased and IC ≈ 0.

Saturation (BJT)

State where both junctions are forward-biased and IC is at maximum.

Load Line

Graphical line on transistor output curves showing all possible IC-VCE combinations for a given load.

Forward Active Region

BJT operating region with forward-biased BE junction and reverse-biased BC junction; used for amplification.

VCE(sat)

Collector-emitter voltage when a BJT is in saturation (typically 0.1-0.3 V for Si).

Power Dissipation (PD)

Product of VCE and IC; must not exceed device rating.

Derating Factor

Value used to reduce maximum power dissipation at elevated temperatures.