Importance of Materials Processing

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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

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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

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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, ...

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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,

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Cubic Lattices and Main Crystal Faces
Z
Y
X
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Lattice Structures of Semiconductors
Ga
Si
Si
Ga
Ga
Si
Ga
Si
Ga
Si
As
Si
As
Si
Ga
Si
Ga
Ga
Si
Si
Ga
Si
As
Si
As
Si
Ga
Ga
Si
Si
Ga
Si
Ga
Ga
Si
Si
Silicon, a 5.43 Å (diamond structure)
GaAs, a 5.65 Å (zincblende structure)
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Point Defects
impurities
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1D 2D Defects
Edge Dislocation
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Real Device Structures in IC
metal contacts
n
p
n
Diode
Bipolar transistor
MOSFET
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N-channel MOSFET (Metal-oxide-semiconductor FET)
Primary flat edge along 110
Schematic vs. Real
Secondary flat
Si(001) wafer
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Fabrication of a Diode
wafer cut
diffusion
oxidation
lithography
diffusion
(f) metallization
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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