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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
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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
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, …
Lattice Structures of Semiconductors Si Ga Si Ga Ga Si Si Ga Si Ga As Si Si As Si Ga Si Ga Ga Si Ga Si As Si As Si Ga Si Si Ga Si Ga Ga Si Si Ga Silicon, a = 5.43 Å (diamond structure) GaAs, a = 5.65 Å (zincblende structure)
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