Download Chap2_MaterProcess

Importance of Materials Processing
 All electronic devices & systems are made of materials in
various combinations
 Raw materials are far from the final electronic products
 Semiconductor materials (e.g., Si, Ge, GaAs, GaN...) used for
devices must be of extremely high purity and crystalline order
Real Materials and their Processing
 Particles, lines and rigid bodies vs. real materials
 Material-specific properties determine the function
and processing details of a material
 Comprehensive knowledge of materials processing
requires ~ 5-10 years of learning and practice
 Advantage and role of physics students
Different Types of Electronic Devices
 Discrete devices: diodes, transistors, rectifiers, sensors, …
 Integrated circuits (IC): CPU, DRAM, ASIC, …
 Opto-electronics: LED, semiconductor laser (in CD/VCD players,
optical communication), display, lighting, …
 Solar cells: on satellites, calculators, large-scale power generation
 Data storage: DRAM, hard disk, ZIP, flush memory, CD-ROM, ...
 Electro-mechanic devices: electro-magnetic, piezo-electric, ...
Different Electronic Materials

Semiconductors: Elemental (Si, Ge) & Compound (GaAs, GaN,
ZnS, CdS, …)

Insulators: SiO2, Al2O3, Si3N4, SiOxNy, ...

Conductors: Al, Au, Cu, W, silicides (metal-Si compounds), ...

Organic and polymer: liquid crystal, insulator, semiconductor,
conductor

Composite materials: multi-layer structures, nano-materials,
photonic crystals, ...

More: magnetic, superconductor, bio-material, …
Cubic Lattices and Main Crystal Faces
Z
Y
X
Lattice Structures of Semiconductors
Si
Ga
Si
Si
Si
Ga
Si
Si
Si
Ga
As
As
Si
Ga
Si
Ga
Si
Ga
Ga
Si
Si
As
Si
Si
Si
Silicon, a = 5.43 Å
(diamond structure)
As
Ga
Si
Si
Ga
Ga
Si
Ga
Ga
Ga
GaAs, a = 5.65 Å
(zincblende structure)
Ga
Point Defects
impurities
1D & 2D
Defects
Edge Dislocation
Real Device Structures in IC
metal contacts
n+
p
n
Diode
Bipolar transistor
MOSFET
N-channel MOSFET
(Metal-oxide-semiconductor FET)
Primary
flat edge
along [110]
Schematic vs. Real
Secondary
flat
Si(001) wafer
Fabrication of a Diode
wafer cut
diffusion
oxidation
lithography
diffusion
(f) metallization
Processes involved in
Semiconductor device
and IC manufacture
Crystal growth and
wafer preparation
Epitaxy
Diffusion
Ion implantation
Oxidation
Lithography
Diffusion
Etching
Deposition
Connection
Testing
Packaging