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Coefficient of Thermal Expansion (CTE)

Definition: The coefficient of thermal expansion is defined as the fractional increase in the length per unit rise in temperature.

The coefficient of thermal expansion for a material is usually specified over a temperature range because it varies depending on the temperature. The following values are given for a temperature around 20 °C. CTE is usually given in units of um/m/°C or ppm/°C.

MaterialCTE (ppm/°C)MaterialCTE (ppm/°C)
AlAs4.9InAs4.52
AlP4.5InP4.75
Alumina7-JunInSb5.37
AsSb4Invar1.3
Copper16.7Kovar5.9
Cu/I/Cu8.4Molybdenum7.0-7.1
Cu/Mo/Cu6Polymers50-200
Cu/Mo-Cu/Cu10-JunS-glass16
E-glass54Silicon2.6
Epoxy55Silicon Nitride (Si3N4)3.2
Fused Silica0.55Silicone resins30-300
Gallium Arsenide (GaAs)6.86Tin-Lead Solder27
GaP4.5Titanium9.5
GaSb7.75Tungsten5.7-8.3
Germanium (Ge)5.8

Sources:www.owlnet.rice.edu/~msci301/ThermalExpansion.pdf
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