Material Properties

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Listing of Some Material Parameters Relevant to Uses with Electronic Circuits.

Electrical

  • Resistivity
  • Dielectric Constant, Dielectric Strength (Breakdown), etc.
  • Band Structures, Band Gap
  • Mobility
  • Wide Range of Device Characteristics
  • Contact Potentials

Chemical

  • Chemical Activity for Processes, Degradation
  • Chemical Bonding
  • Electrical Affinity
  • Phase Diagrams
  • Chemical Potential

Thermal

  • Melt Point
  • Latent Heats of Phase Transformations (Fusion, etc.)
  • Thermal Expansion
  • Vapor Pressure, Sublimation
  • Diffusion Coefficient
  • Specific Heat
  • Thermal Conductivity

Mechanical

  • Elastic Modulus (Various)
  • Tensile Strength
  • Elastic-Plastic Characteristics, Yield Point, etc.
  • Toughness, Hardness
  • Fatigue Durability
  • Poisson's Ratio
  • Acoustical
  • Creep
  • Friction, Adhesion, Wear

Structural

  • Single Crystal, Polycrystal, Amorphous, Epitaxial, etc.
  • Crystal Structure
  • Relevant Crystal Transformations
  • Relevant Crystal Defects
  • Optical
  • Fluorescense
  • Reflectivity
  • Refractive Index
  • Electroluminescense
  • Birefrengence

Radiation

  • Cross Sections, Neutron, Ionizing Radiation
  • X-Ray Absorption, Fluorescense
  • Radiation Damage Effects
  • Scattering

Cross Discipline Effects

  • Magnetomechanical (Magnetostriction)
  • Chemomechanical
  • Electrochemical
  • Mechano-electric (Piezoelectric)
  • Electro-optical (Photovoltaic, Photoelectron, Photoelectrolysis)
  • Electro-optical, LASER, LED
  • Magneto-optical
  • Thermoelectric
  • Thermomechanical, Expansion-contraction, Glass Transitions

Physical Properties of Semiconductor Materials

Physical Properties of Several Semiconductors and Diamond
Material Density (g/cm3) Hardness (kg/mm2) Flexure Strength (KPSI) Young's Modulus (GPa) Thermal Exp. Coeff. (10-6/oK) at 23oC Thermal Exp. Coeff. (10-6/oK) at 200oC Specific Heat
(J/gmoK)
Thermal Conductivity (W/cmoK) Band Gap (eV)
ZnS 4.08 230 14 74.5 6.8 7.7 0.468 0.17 3.58
GaAs 5.32 700 8 85.5 5.7 6.4 0.345 0.53 1.43
GaP 4.13 845 15 102.6 5.3 5.8 0.435 0.97 2.24
Si 2.33 1150 18.5 130.1 2.3 2.9 0.758 1.41 1.12
Ge 5.32 850 13.5 103.3 6.0 Liquid 0.310 0.60 0.67
Diamond 3.52 9000 427 1050 1.0 2.0 0.515 26.00 5.40
Data compiled by Texas Instruments

Phase Diagrams

Aluminum - Silicon Phase Diagram

Lead - Tin Phase Diagram

Aluminum - Gold Phase Diagram

Gold - Silicon Phase Diagram

Aluminum - Copper Phase Diagram

Titanium - Tungsten Phase Diagram

Gold - Tin Phase Diagram

Copper - Tin Phase Diagram

Titanium - Aluminum Phase Diagram

Aluminum - Tungsten Phase Diagram

Coefficients of Thermal Expansion and Resistivity

Thermal mismatch between materials is a major source of concern in microelectronics. A large mismatch in the coefficient of thermal expansion (TCE) between two bonded materials can result in large stresses and even cracking, delamination, or other types of failure. The following graphs show various TCE values for selected materials used in microelectronics processing and packaging. The larger the difference, the more concern there is for failure.

Coefficients of Thermal Expansion (Higher) for Selected Microcircuit Materials (see Figure 12)

Coefficients of thermal expanision for common semiconductor materials

Coefficients of Thermal Expansion (Lower and Polymers) for Selected Microcircuit Materials (see Figure 13)

Coeffiencients of thermal expanision for common semiconductor and print circuit board materials.

Resistivity of Metals

Metal systems used in microelectronics are typically tradeoffs between performance, reliability, ease of which to process, and contamination issues. Resistivity is typically an important factor when considering circuit performance. Below is a graph of resistivity for various metals used in microelectronic processing.

Resistivity Values for Various Metals (see Figure 14).

Resistivity values for various metals.

Thermal Conductivity Values for Various Metals (see Figure 15).

Thermal conductivity of various metals.