Electronic Material Science

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Electronic Material Science

• Introduction

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What is EMS?

• EMS centres on the study of the structure
  physical properties of solid materials
• The field encompasses the spectrum of materials

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Types of Materials

• Metals
• Ceramics
• Polymers
• Semiconductors
• Composites

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Metals

• Combinations of metallic elements
• Characterised by non-localised electrons
• Good conductors of heat electricity
• Strong, malleable lustrous when polished

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Ceramics

• Compounds of metallic non-metallic elements
• Include oxides, nitrides carbides
• Good insulators
• Resistant to high temperatures harsh
  environments

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Polymers (Plastics)

• Organic compounds based on carbon hydrogen
• Very large molecular structures (chains)
• Low density
• Unstable at high temperatures

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Semiconductors

• Electrical properties intermediate between metals
  ceramics
• Electrical properties are strongly dependent upon
  small amounts of impurities (doping)

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Composites

• Consist of more than one material type
• concrete plywood
• ceramic fibres in metal or plastic
• carbon/aramid fibres in plastic
• strong yet flexible
• low density

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Elements of Material Selection

• Processing
• Structure
• Properties
• Performance

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Processing

• Solidification - molten (alloys)casting heat
  treat
• Powder - pressing (densification) sintering
• Deposition - electroplating chemical vapour
  deposition sputtering laser ablation
• Deformation - rolling forging extrusion
  drawing

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Structure

• Arrangement of components from material to macro
  scale
• Serves to understand processing requirements
  physical properties

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Properties

• Mechanical
• Electrical
• Thermal
• Magnetic
• Optical Dielectric
• Environmental

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Performance

• Testing characterisation at various stages
• Analysis of failed products
• Slide shows SEM micrograph of an alumina ceramic
  during bending

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Interrelation of Elements

• Aluminium Oxide
• Sapphire - crystalline/transparent
• Pollycrystalline nonporous/translucent
• Pollycrystalline 5 porosity/opaque
• Different-
• process
• structure
• properties
• performance

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Brief History of Materials
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Milestones of Progress 1
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Milestones of Progress 2
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Milestones of Progress 3
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Milestones of Progress 4
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Milestones of Progress 5
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Milestones of Progress 6
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Milestones of Progress 7

• 1940s - Zone Refining, a purification process
  critical to the emergence of silicon technology
• 1955 - Polymerisation catalysts discovered
  opened the way for new range of plastics

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Milestones of Progress 8
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Milestones of Progress 9
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Carbon/Aramid Fibre Composites - 1990s
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Chip Fabrication
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Moores Law

• Transistor densities on ICs have increased at an
  exponential rate
• Rate sustained by a succession of litography
  systems
• Higher rate in memory chips due to simpler design

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The Spectrum of Materials
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Summary

• The processing, structure, properties
  performance of materials are closely interrelated
  
• This course will focus on the structure of
  materials on their physical properties
• New materials are being developed at an
  unprecedented rate