Charp 7表面.ppt

Charp 7;7.1 Realistic and Ideal Surfaces; The local variations related to defects may cause changes in all important surface properties, such as bonding behavior, atomic coordination, electronic states, lattice vibrations, etc. A through study of such defects is therefore important for a fundamental understanding of their role in growth nucleation/epitaxy (evaporation, surface diffusion, adsorption, and desorption), surface chemical reactions (e.g. the surface catalytic efficiency), and electronic devices (surface carrier recombination, Fermi-level pinning).;7.2 Point Defects; The characteristic quantity that governs the probability of the appearance in thermodynamic equilibrium is the formation energy; The charge state of the anion vacancy in the surface layer determines the atomic relaxation around the defect (in contrast to bulk) and the energetics of its formation.; According to the formation energy the most favorable charge state depends on the doping level.;Impurities;Antisites;7.3 Line Defects: Steps;Steps on Si(100) Surfaces;Steps on Si(111) Surfaces;7.4 Planar Defects: Stacking Faults;期末复习;2，表面外延生长有哪三种模式并分析其原因;4, 试根据Ga和As在GaAs(110)上的势能面估算室温下原子沿不同方向的平均跳跃速度（p102-109）;6, 试写出半导体表面重构的基本结构单元;8，试写出表面缺陷的种类