Concept Taxonomy
16 categories for the Semiconductor Physics: Fundamentals to Advanced Applications course.
FOUND — Foundation Concepts
TaxonomyID: FOUND
Basic definitions, introductory material properties, and the bandgap concept that serves as the entry point for all semiconductor physics topics. These concepts have no prerequisites and are the starting points for the learning graph.
Concepts: Semiconductor Definition, Conductor vs Insulator vs Semiconductor, Elemental Semiconductors, Compound Semiconductors, Silicon/Germanium/GaAs/InP/GaN/SiC material properties, Bandgap Energy, Direct/Indirect Bandgap, Energy Band Diagram, Conduction/Valence Bands, Forbidden Energy Gap.
CRYST — Crystal Structure and Defects
TaxonomyID: CRYST
Crystallography fundamentals including lattice types, unit cells, Miller indices, reciprocal space, diffraction, bonding types, and crystal imperfections (point defects, dislocations, surfaces). Foundational for understanding why real semiconductors behave differently from ideal models.
Concepts: Crystal Lattice, Unit Cell, Primitive Cell, Basis Vectors, cubic/diamond/zincblende/wurtzite structures, Miller Indices, Reciprocal Lattice, Brillouin Zone, Bragg Law, X-ray/Electron Diffraction, Covalent/Ionic/Metallic/Van der Waals Bonding, SP3 Hybridization, Point Defects, Vacancies, Interstitials, Dislocations, Surface/Interface States, Dangling Bonds.
QM — Quantum Mechanics
TaxonomyID: QM
Quantum mechanical foundations including wave-particle duality, the Schrödinger equation, energy quantization, tunneling, atomic structure, and the Bloch/Kronig-Penney models that explain the origin of energy bands in solids.
Concepts: Wave-Particle Duality, de Broglie Wavelength, Heisenberg Uncertainty Principle, Schrödinger Equation (time-dependent and independent), Wave Function, Probability Density, Particle in a Box, Potential Wells, Quantum Tunneling, WKB Approximation, Hydrogen Atom, Atomic Orbitals, Quantum Numbers, Pauli Exclusion Principle, Electron Spin, Spin-Orbit Coupling, Perturbation Theory, Kronig-Penney Model, Bloch Theorem, Periodic Potential.
BAND — Band Theory
TaxonomyID: BAND
Energy band structure including free electron and tight-binding models, E-k diagrams, effective mass tensor components, hole quasi-particles, valence band structure (heavy holes, light holes, split-off band), and density of states in 3D/2D/1D/0D systems.
Concepts: Free/Nearly-Free/Tight-Binding Electron Models, LCAO, E-k Dispersion Relation, Effective Mass Approximation (longitudinal, transverse, DOS, conductivity), Crystal Momentum, Band Gap Origin, Hole Concept, Hole/Heavy/Light Hole Effective Mass, Split-Off Band, Spin-Orbit Splitting, Density of States in 3D/2D/1D/0D.
STAT — Carrier Statistics and Equilibrium
TaxonomyID: STAT
Statistical mechanics of charge carriers in equilibrium: Fermi-Dirac and Maxwell-Boltzmann distributions, carrier concentration formulas, doping physics, Fermi level position, and ionization/compensation effects across temperature regimes.
Concepts: Fermi Energy, Fermi Level, Fermi-Dirac/Maxwell-Boltzmann Distributions, Effective DOS, Intrinsic Carrier Concentration, Law of Mass Action, N/P-Type Doping, Donor/Acceptor Atoms, Group III/V Dopants, Ionization Energy, Complete Ionization, Freeze-Out/Extrinsic/Intrinsic Regimes, Majority/Minority Carriers, Degenerate/Non-Degenerate Semiconductors, Compensation Doping, Fermi Level in N/P-Type.
TRANS — Carrier Transport
TaxonomyID: TRANS
Charge carrier motion under electric fields and concentration gradients: drift and diffusion currents, mobility and its scattering mechanisms, the Einstein relation, resistivity, Hall effect, and the continuity and ambipolar transport equations.
Concepts: Drift/Diffusion Current, Drift Velocity, Carrier Mobility, Velocity Saturation, Hot Carriers, Lattice/Phonon/Impurity Scattering, Matthiessen Rule, Mobility vs Temperature/ Doping, Diffusion Coefficient, Einstein Relation, Resistivity, Conductivity, Sheet Resistance, Hall Effect, Magnetoresistance, Continuity Equation, Ambipolar Transport, Minority Carrier Lifetime/Diffusion Length, Piezoresistance.
GREC — Generation and Recombination
TaxonomyID: GREC
Non-equilibrium carrier dynamics: recombination mechanisms (direct/radiative, SRH trap-assisted, Auger, surface), optical absorption and generation, quasi-Fermi levels, and injection level regimes.
Concepts: Direct/Band-to-Band/Radiative Recombination, SRH/Trap-Assisted Recombination, Trap Density/Energy/Capture Cross Section, Auger Recombination, Surface Recombination Velocity, Optical Absorption/Absorption Coefficient, Optical Generation Rate, Photoconductivity, Quasi-Fermi Levels, Quasi-Fermi Level Splitting, Low/High-Level Injection, Excess Carriers.
PNJ — P-N Junction and Diodes
TaxonomyID: PNJ
P-N junction electrostatics and device physics: depletion region, built-in potential, bias conditions, ideal diode equation, current components, breakdown mechanisms, junction capacitance, switching transients, and heterojunction band alignment.
Concepts: P-N Junction, Depletion Region/Width/Approximation, Built-In Potential, Forward/Reverse Bias, Band Diagrams Under Bias, Ideal Diode Equation, Shockley Equation, Saturation/G-R/Tunneling Currents, Avalanche/Zener Breakdown, Junction/Depletion/Diffusion Capacitance, Reverse Recovery, Heterojunction, Band Alignment Types, Anderson Rule.
MIS — Metal-Semiconductor and MOS Structures
TaxonomyID: MIS
Metal-semiconductor contacts (Schottky and ohmic), thermionic emission, Fermi level pinning, the MOS capacitor from accumulation to inversion, threshold voltage, oxide charges, C-V characteristics, and gate oxide reliability.
Concepts: Work Function, Electron Affinity, Schottky-Mott Rule, Schottky Barrier/Height, Thermionic Emission, Ohmic/Tunneling Contacts, Specific Contact Resistance, Fermi Level Pinning, Metal-Induced Gap States, MOS Capacitor, Accumulation/Depletion/Inversion Regions, Flat-Band Voltage, Threshold Voltage, Body Effect, Oxide Charges, C-V Characteristics, Gate Oxide Breakdown, TDDB.
BJT — Bipolar Junction Transistors
TaxonomyID: BJT
NPN/PNP bipolar transistor physics: injection efficiency, base transport, current gain (α, β), operating regions, Ebers-Moll and Gummel-Poon models, Early effect, Kirk effect, high-frequency limits (ft, fmax), and heterojunction bipolar transistors (HBTs).
Concepts: Bipolar Junction Transistor, NPN/PNP Structures, Operating Regions, Common- Emitter/Base/Collector Configurations, Emitter Injection Efficiency, Base Transport Factor, Current Gains α and β, Ebers-Moll/Gummel-Poon Models, Early Effect, Kirk Effect, Transition/ Maximum Oscillation Frequencies, HBT.
FET — Field-Effect Transistors
TaxonomyID: FET
JFET, MESFET, and MOSFET physics: long-channel I-V model, transconductance, subthreshold behavior, channel-length modulation, short-channel effects (DIBL, punch-through, velocity saturation), CMOS technology, and advanced structures (FinFET, GAA, SOI, nanowire).
Concepts: JFET/MESFET/MOSFET Structure and Operation, N/P-Channel and Enhancement/Depletion Modes, Triode/Saturation/Cutoff Regions, Threshold Voltage, Long-Channel I-V, Transconductance, Subthreshold Swing, Gradual Channel Approximation, Short-Channel Effects, DIBL, CMOS Inverter, FinFET, GAA Transistor, SOI MOSFET, Dennard Scaling.
OPT — Optoelectronic Devices
TaxonomyID: OPT
Light-emitting devices (LEDs, lasers, VCSELs), light-detecting devices (photodiodes, APDs, CCDs, CMOS image sensors), and photovoltaics (solar cells), including efficiency limits, optical cavities, population inversion, and the Shockley-Queisser limit.
Concepts: LED (operation, materials, efficiency), Laser Diode (threshold, cavities, DBR, DFB, VCSEL, DHS, quantum-well), Photodiode (PIN, responsivity, bandwidth, APD), Solar Cell (I-V, fill factor, efficiency, Shockley-Queisser, multi-junction), CCD/CMOS Image Sensors.
ADV — Advanced Materials and Structures
TaxonomyID: ADV
III-V and II-VI compound semiconductors, wide-bandgap materials (GaN, SiC), quantum wells/ wires/dots, 2DEG and HEMTs, strained layers, and emerging 2D materials (graphene, TMDs, carbon nanotubes).
Concepts: III-V (GaAs, InP, InGaAs, AlGaAs, InGaAsP), II-VI Compounds, Wide-Bandgap (GaN, SiC, AlGaN), Quantum Well/Wire/Dot Structures, Subband Structure, Size Quantization, 2D Electron Gas, HEMT (Pseudomorphic, Metamorphic), Strained Silicon, Critical Thickness, Graphene, Transition Metal Dichalcogenides (MoS₂), Van der Waals Heterostructures, Carbon Nanotubes, Quantum Confinement Effects.
PWR — Power and Microwave Devices
TaxonomyID: PWR
High-voltage and high-power semiconductor devices including power diodes, thyristors, IGBTs, power MOSFETs, and microwave devices (Gunn, IMPATT, negative-resistance), plus breakdown engineering and cutoff frequency limits.
Concepts: Power Diode, Thyristor, SCR, IGBT, Power MOSFET, Superjunction MOSFET, High-Voltage Device Design, Breakdown Engineering, Gunn Diode/Effect, Transferred Electron Effect, IMPATT Diode, Negative Resistance Devices, Microwave Parasitics, Cutoff Frequency.
FAB — Fabrication Concepts
TaxonomyID: FAB
Semiconductor fabrication processes that affect device physics: crystal growth (Czochralski, float-zone), epitaxy (MBE, MOCVD, CVD), oxidation, diffusion, ion implantation, photolithography, etching, thin-film deposition, metallization, and process-induced defects.
Concepts: Czochralski/Float-Zone Crystal Growth, Epitaxial Growth, MBE/MOCVD/CVD, Thermal Oxidation/Deal-Grove Model, Diffusion (Fick's Laws), Ion Implantation/Range Distribution/ Channeling/Annealing, Photolithography/Photoresist, Etching (wet/dry/RIE), PVD/Sputtering, Metallization, Silicide Formation, Process-Induced Defects, Yield Engineering.
CHAR — Characterization and Device Modeling
TaxonomyID: CHAR
Experimental characterization techniques (I-V, C-V, Hall, four-point probe, DLTS, optical, electron microscopy, SIMS) and device modeling (SPICE compact models, BSIM, small/large-signal circuits, noise, tunneling devices, ballistic transport).
Concepts: I-V/C-V/Hall Measurements, Four-Point Probe, DLTS, Photoluminescence/ Electroluminescence/Raman Spectroscopy, TEM/SEM/SIMS/Auger Spectroscopy, SPICE Compact Models, Level-1 MOSFET/BSIM Models, Small/Large-Signal Circuits, Noise (thermal, shot, flicker), Noise Figure, Band-to-Band Tunneling, Esaki/Resonant Tunneling Diodes, Negative Differential Resistance, Ballistic Transport.