1 The Crystal Structure of Solids
1.3 Space Lattices
lattice point 晶格点
unit cell a small volume of the crystal that can be used to reproduce the entire crystal
primitive cell the smallest unit cell that can be repeated to form the lattice.
1.3.2 Basic Crystal Structures
Volume Density of Atoms
1.5 (b)
Three lattice types:
(a) simple cubic, (b) body-centered cubic, (c) face-centered cubic.
1.3.3 Crystal Planes and Miller Indices
surface matters a lot
the intercepts of the plane 平面的截距
Miller indices
hkl plane
取截距倒数？the use of infinity is avoided
take the reciprocal（倒数） of the intercepts（截距）
distance between nearest equivalent parallel planes
surface concentration
surface density
1.3.4 Directions in Crystals
[1,1,1]平面法向量
1.4 The Diamond Structure
tetrahedral 四面体
zincblende (sphalerite) structure
1.5 Atomic Bonding
qualitative understanding
valence electrons 价电子
ions 离子
coulomb attraction 库伦吸引
ionic bond 离子键
NaCl
covalent bonding 共价键
H~2~
the outer silicon atoms always have valence electrons available for additional covalent bonding - infinite structure
metallic bonding 金属键
Van der Waals bond 范德华~
nonsymmetry - small electric dipole - interact with each other
1.6 imperfections and impurities in solids
electrical parameters
1.6.1 imperfections in solids
atomic thermal vibration
lattice vibration
thermal energy(function of temperature) - atom randomly fluctuate
point defect
lack of an atom - vacancy
多了一个 interstitial
- Frenkel defect
line dislocation
1.6.2 impurities in Solids
lattice defects
substitutional impurities
interstital impurities
doping (参杂原子)
- impurity diffusion
high temperature - vacancy - impurity partical move from high concentration to lower - low down the temp
- ion implantation
low temp - ions be accelerated
defect: lattice displacement damage
solve: thermal anneal 热退火
1.7 growth of semiconductor materials
1.7.1 growth from a melt
Czochralski Method（Growth）
seed - the same material in liquid phase - pulled - bigger
zone refining（Purify）
At the solid–liquidinterface, there is a distribution of impurities between the two phases. The parameter that describes this distribution is called the segregation coefficient: the ratio of the concentration of impurities in the solid to the concentration in the liquid.
r-f coil 射频线圈
切割
flat（110）plane
polish
chemecal etch
1.7.2 Epitaxial Growth
外延生长
single-crystal substrate
homoepitaxy one material
heteroepitaxy e.g. Growing epitaxial layers of the ternary alloy AlGaAs on a GaAs substrate
CVD chemical vapor-phase deposition
chemical reaction release material atom to deposit on the material
Liquid-phase epitaxy
melt temp lower than the semiconductor itself
practiced at low temp (III-V)
Molecular Beam Epitaxy
vacuum iat temp 0f 400-800
semiconductor and dopant atoms evaporated onto the surface of the substrate
1.8 Summary
substrate A semiconductor wafer or other material used as the starting material for further semiconductor processing, such as epitaxial growth or diffusion.
ternary semiconductor A three-element compound semiconductor, such as aluminum gallium arsenide (AlGaAs).
elemental semiconductor A semiconductor composed of a single species of atom, such as silicon or germanium.