《半导体器件物理》1.ppt

§1-1 Introduction Direct Lattice: Bravais Cell Reciprocal Lattice: Wigner-Seitz Cell One-electron Approximation Brillouin ZoneReduced Brillouin Zone §1-4 Carrier Concentration at Thermal Equilibrium Compensated Semiconductor Experiments: Solid-state Diffusion EX. (Gold in silicon) High-energy Radiation EX. (Electron irradiation, Neutron irradiation, Deuteron irradiation) The minority-carrier lifetime measurement PC: Photoconduction Effect Stevenson-Keyes Method PEM: Photo-electromagnetic Effect §1-6 Phonon Spectra and Optical, Thermal, and High-Field Properties of Semiconductors High-Field Property Nonlinear mobility (μ) Effective temperature (Te) Saturation of drift velocity Maxwell Equations (homogeneous isotropic) Current-density Equations Continuity Equations Indirection Recombination at steady state at equilibrium, GL=0 Ra=Rb and Rc=Rdunder steady state nonequilibriumGL= Ra- Rb = Rc- Rd ≡ U Indirection Recombination The Minority-carrier Lifetime (Single-level Recombination) The Asymptotic Lifetime (Multiple-level Recombination) Surface Recombination The abrupt discontinuity of the lattice structure at the surface, a large number if localized energy states or generation recombination centres may be introduced at the surface region. These energy states called surface states, may greatly enhance the recombination rate at the surface region. Low-injection surfacerecombination velocity PHONON SPECTRA LA—longitudinal acoustic modes LO—longitudinal optical modes TA—transverse acoustic modes TO—transverse optical modes Optical Property T----Transmission coefficient R----Reflection coefficient a----absorption coefficient a~(h ν-Eg) γ 1.Phonon scattering-Lattice atoms vibrate with discrete allowable states (quantum mechanics).2.Ionizad impurity atom scattering (important at high dopant concentrations)3.Neutal impurity atom scattering (usually negligible)4.Electron-electron and Electron-hole scattering (important at high carrier concentration